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This registration describes a study done when a cohort of European starlings hand-reared in 2022 were approximately one year old to explore the effects of adult food insecurity.

European starling (Sturnus vulgaris; starling) nesting poses debris hazards within airport hangars and to engine and flight surfaces of moored aircraft. We questioned whether consistent removal of nest material would negatively affect use of a nest site, measured by a reduction in material accumulation. We conducted our study on a 2,200-ha site in Erie County, Ohio, USA (41° 22’ N, 82° 41’ W), from April 15 through June 2, 2020. We used 120 wooden nest boxes on utility poles, protected by an aluminum predator guard below the box. Our treatments included (1) twice weekly, repeated nest material removal (RMR; n = 40 nest boxes); (2) complete nest removal, but only after nest construction and ≥1 starling egg was laid (CNR; n = 40 nest boxes); and (3) a control; n = 40 nest boxes; N = 120 nest boxes). Starlings deposited approximately 50% greater mass of nest material and eggs at RMR than CNR nest boxes, indicating that consistent disturbance failed to dissuade use. Predator guard protection of nest boxes at our site reduced nest predation of starlings; the current starling population is likely adapted to selecting these sites. Similar selection toward low nest-predation risk associated with anthropogenic structures and moored aircraft is also possible. Aside from covering moored aircraft and closing hangar doors, actions not necessarily feasible, removal of starling nesting material more than twice weekly would be necessary to maintain minimum control over material deposition that could affect aircraft function and safety.

European starlings (Sturnus vulgaris) are an invasive species in the United States that damage agriculture, personal property, and threaten human health and safety. The U.S. Department of Agriculture Wildlife Services provides technical support to mitigate damage by controlling starling populations at concentrated animal feeding operations, landfills, utilities, and urban areas. Wildlife Services uses DRC-1339, a registered toxicant, to reduce starling populations. Trapping can also be an effective tool but requires more time at a higher cost than DRC-1339. Trapping starlings, however, may be needed to provide a viable alternative to mitigate damage in areas where toxicant use may be restricted. To address this need, I developed a unique and effective starling trap to increase catch rates. I began testing multiple trap designs in November 2007 at cattle (Bos taurus) feedlots, meat processing plants, and urban staging areas in a 45-km radius of the city of Omaha, Nebraska, USA. In December 2011, I designed a 4-chamber, basket-style starling trap that has been instrumental in a nearly 90% reduction of the roosting starling population in downtown Omaha. Herein, I discuss the development and testing of the trap and provide guidelines and instructions for building and strategic placement of the trap.

Wild birds cause significant damage to dairy farms through the consumption and spoilage of cattle feed. A survey of Washington State dairy farmers revealed approximately $14 million in bird damage losses for the Washington State dairy industry, annually. Furthermore, farms that reported the presence of more than 10,000 birds per day were more likely to report the presence of Salmonella spp. or Johne’s disease (caused by Mycobacterium avium subsp. paratuberculosis). Over the course of three years, we assessed the impact of bird populations on the presence of bacteria in bird feces and the nutritional composition of cattle feed. Five dairies were enrolled into the study and visited to collect bird fecal samples and cattle feed samples. Several pens were monitored on each dairy. Bird fecal samples were analyzed for three bacterial populations. Fresh and bird-depleted feed samples were analyzed for dry matter, total digestible nutrients, protein, crude fiber, ash, fat, and net energy. The prevalence of bacterial populations in bird fecal samples did not differ among farms, but Campylobacter jejuni, a bacterial strain known for causing abortions in cattle, was discovered in one location. The number of birds observed at the feed bunk and the percentage of nutritional loss in cattle feed differed among pens. Understanding where birds prefer to feed on dairies may improve the effectiveness of bird deterrent management techniques. A variety of bird deterrent methods are available for dairy farmers but, at best, the most commonly used methods were considered only “somewhat effective” by farmers. The use of more sustainable methods, such as attracting native birds of prey to dairies, may be beneficial to dairy cattle well-being as well as dairy farmer economic sustainability.

Since their intentional introduction into the United States in the 1800s, European starlings (Sturnus vulgaris) have become the fourth most common bird species and a nuisance bird pest in both urban and rural areas. Managers require better information about starling movement and habit-use patterns to effectively manage starling populations and the damage they cause. Thus, we revisited 6 radio-telemetry studies conducted during fall or winter between 2005 and 2010 to compare starling movements (n = 63 birds) and habitat use in 3 landscapes. Switching of roosting and foraging sites in habitat-sparse rural landscapes caused daytime (0900–1500 hours) radio fixes to be on average 2.6 to 6.3 times further from capture sites than either urban or exurban landscapes (P < 0.001). Roosts in urban city centers were smaller (100,000 birds) 6–13 km away in industrial zones. Radio-tagged birds from city-center roosts occasionally switched to the outlying major roosts. A multitrack railroad overpass and a treed buffer zone were used as major roosts in urban landscapes. Birds traveling to roosts from primary foraging sites in exurban and rural landscapes would often pass over closer-lying minor roosts to reach major roosts in stands of emergent vegetation in large wetlands. Daytime minimum convex polygons ranged from 101–229 km2 (x̄ = 154 km2). Anthropogenic food resources (e.g., concentrated animal feeding operations, shipping yards, landfills, and abattoirs) were primary foraging sites. Wildlife resource managers can use this information to predict potential roosting and foraging sites and average areas to monitor when implementing programs in different landscapes. In addition to tracking roosting flights, we recommend viewing high-resolution aerial images to identify potential roosting and foraging habitats before implementing lethal culls (e.g., toxicant baiting).

Common pest birds in the United States include the non-native European starling (Sturnus vulgaris), house sparrow (Passer domesticus), and the pigeon (Columba livia domestica), as well as native birds including Canada geese (Branta canadensis) and gull species (Laridae). Large concentrations of pest birds can create human health hazards and monetary losses due to consumption of crops, depredation, and fecal contamination and accumulation. Fecal contamination hazards include the potential spread of zoonotic diseases including antimicrobial-resistant zoonoses and human injury due to the accumulation of fecal material on walking surfaces. Additionally, fecal accumulation causes structural and aesthetic damage due to the accelerated deterioration of building materials and increased maintenance costs. Methods to alleviate hazards and damages from aggregations of pest birds are needed. In a series of 3 experiments conducted in Fort Collins, Colorado, USA, between 2016 and 2018, we evaluated 3 surface-application repellent formulations for the reduction of fecal accumulations due to European starlings: Airepel® HC with castor oil, an anthraquinone-based repellent; Airepel HC with castor oil without anthraquinone; and MS2, a novel inert formulation with a tacky, oily texture. We compared each formulation directly to an untreated control. All 3 formulations reduced fecal accumulations beneath treated aluminum perches as compared to fecal accumulations beneath untreated aluminum perches. Interestingly, both formulations that contained no anthraquinone worked equally well or better than Airepel HC with castor oil, the anthraquinone-based formulation. The benefits of an exclusively inert formulation include less risk to applicators and non-target species. Comprehensive experimental field testing of these surface-application repellent formulations is warranted.

The European Starling (Sturnidae: Sturnus vulgaris L.) is an invasive bird in North America where it is an agricultural pest. In British Columbia (Canada), the starling population increases in orchards and vineyards in autumn, where they consume and damage ripening fruits. Starlings also cause damage in dairy farms and feedlots by consuming and contaminating food and spreading diseases. Damage can be partly mitigated by the use of scare devices, which can disperse flocks until they become habituated. Large-scale trapping and euthanizing before starlings move to fields and farms could be a practical means of preventing damage, but requires knowledge of natal origin. Within a small (20,831 km2), agriculturally significant portion of south-central British Columbia, the Okanagan-Similkameen region, we used 21 trace elements in bone tissue to discriminate the spatial distribution of juvenile starlings and to reveal the geographic origin of the problem birds in fall. Stepwise discriminant analysis of trace elements classified juveniles to their natal origin (minimum discrimination distance of 12 km) with 79% accuracy. In vineyards and orchards, the majority (55%) of problem birds derive from northern portions of the valley; and the remaining 45% of problem birds were a mixture of local and immigrant/unassigned birds. In contrast, problem birds in dairy farms and feedlots were largely immigrants/unassigned (89%) and 11% were local from northern region of the valley. Moreover, elemental signatures can separate starling populations in the Valley yielding a promising tool for identifying the geographic origin of these migratory birds.

The European starling, Sturnus vulgaris, is a prolific and worldwide invasive species that also has served as an important model for avian ecological and invasion research. Although the genome sequence recently has become available, no transcriptome data have been published for this species. Here, we have sequenced and assembled the S. vulgaris liver transcriptome, which will provide a foundational resource for further annotation and validation of the draft genome. Moreover, it will be important for ecological and evolutionary studies investigating the genetic factors underlying rapid evolution and invasion success in this global invader.

Simple Summary European starlings are an abundant, widespread avian species frequently found in close association with human development and agriculture. Do starlings play a role in transmitting disease to humans or domestic livestock? To investigate the importance of European starlings as disease vectors, I reviewed and assessed the available literature, comprising several hundred published papers. Although a wide variety of potential pathogens have been reported in starlings, the strongest evidence suggests that they may be responsible for harboring and dispersing some species of enteric bacteria, with Escherichia coli and Campylobacter jejuni of perhaps greatest interest, and primarily in the context of dairies, concentrated animal feeding operations, and other intensive livestock agriculture. Although they can carry other pathogens like Salmonella and influenza viruses, evidence suggests they are not as important in the ecology of these diseases. Abstract European starlings are an abundant, widespread avian species frequently found in close association with human development and agriculture. The ability of starlings to carry and disperse pathogens of humans and domesticated livestock has received considerable attention, including studies of enteric bacteria, viruses, and some fungi. To investigate the importance of European starlings as disease vectors, I reviewed and assessed the available literature, comprising several hundred published papers. Although a wide variety of potential pathogens have been reported in starlings, the strongest evidence suggests that they may be responsible for harboring and dispersing some species of enteric bacteria, with Escherichia coli and Campylobacter jejuni of perhaps greatest interest, and primarily in the context of dairies, concentrated animal feeding operations, and other intensive livestock agriculture.

Avian influenza A viruses (IAV) have received significant attention due to the threat they pose to human, livestock, and wildlife health. In this review, we focus on what is known about IAV dynamics in less common avian species that may play a role in trafficking IAVs to poultry operations. Specifically, we focus on synanthropic bird species. Synanthropic species, otherwise known as peridomestic, are species that are ecologically associated with humans and anthropogenically modified landscapes, such as agricultural and urban areas. Aquatic birds such as waterfowl and shorebirds are the species most commonly associated with avian IAVs, and are generally considered the reservoir or maintenance hosts in the natural ecology of these viruses. Waterfowl and shorebirds are occasionally associated with poultry facilities, but are uncommon or absent in many areas, especially large commercial operations. In these cases, spillover hosts that share resources with both maintenance hosts and target hosts such as poultry may play an important role in introducing wild bird viruses onto farms. Consequently, our focus here is on what is known about IAV dynamics in synanthropic hosts that are commonly found on both farms and in nearby habitats, such as fields, lakes, wetlands, or riparian areas occupied by waterfowl or shorebirds.

Animals can insure themselves against the risk of starvation associated with unpredictable food availability by storing energy reserves or gathering information about alternative food sources. The former strategy carries costs in terms of mass-dependent predation risk, while the latter trades off against foraging for food; both trade-offs may be influenced by an individual's developmental history. Here, we consider a possible role of early developmental experience in inducing different mass regulation and foraging strategies in European starlings. We measured the body mass, body condition, foraging effort, food consumption and contrafreeloading (foraging for food hidden in sand when equivalent food is freely available) of adult birds (≥10 months old) that had previously undergone a subtle early life manipulation of food competition (cross-fostering into the highest or lowest ranks in the brood size hierarchy when 2–12 days of age). We found that developmentally disadvantaged birds were fatter in adulthood and differed in foraging behaviour compared with their advantaged siblings. Disadvantaged birds were hyperphagic compared with advantaged birds, but only following a period of food deprivation, and also spent more time contrafreeloading. Advantaged birds experienced a trade-off between foraging success and time spent contrafreeloading, whereas disadvantaged birds faced no such trade-off, owing to their greater foraging efficiency. Thus, developmentally disadvantaged birds appeared to retain a phenotypic memory of increased nestling food competition, employing both energy storage and information-gathering insurance strategies to a greater extent than their advantaged siblings. Our results suggest that subtle early life disadvantage in the form of psychosocial stress and/or food insecurity can leave a lasting legacy on foraging behaviour and mass regulation even in the absence of food insufficiency during development or adulthood.

The aim of this work is to contribute to the knowledge of gastrointestinal parasites of the European starling Sturnus vulgaris, an invasive bird from Argentina. Seventy-six birds were collected during the spring of 2007 and were examined for helminths. Six parasite species were found: one trematoda of the Echinostoma revolutum group, four nematodes (Synhimantus nasuta, Microtetrameres sp., Pterothominx exilis, and Ornithocapillaria ovopunctata), and one acanthocephalan (Plagiorhynchus cylindraceus). All species found have been recorded in Eurasia and/or North America previously, although present reports enlarge their geographical distribution. As expected in an invasive host, the parasite community shows much lower species richness (n = 6) than those observed in their native area (79 and 35 in the Eurasia and North America, respectively). Fil: Valente, Romina. Ministerio de Salud. Instituto Nacional de Medicina Tropical; Argentina Fil: Ibañez, Lucía Mariel. Universidad Nacional de la Plata. Facultad de Ciencias Naturales y Museo; Argentina Fil: Lorenti, Eliana Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Centro de Estudios Parasitológicos y de Vectores (i); Argentina Fil: Fiorini, Vanina Dafne. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentina Fil: Montalti, Diego. Universidad Nacional de la Plata. Facultad de Ciencias Naturales y Museo; Argentina Fil: Diaz, Julia Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Centro de Estudios Parasitológicos y de Vectores (i); Argentina

Exercise is known to have a strong effect on neuroproliferation in mammals ranging from rodents to humans. Recent studies have also shown that fatty acids and other dietary supplements can cause an upregulation of neurogenesis. It is not known, however, how exercise and diet interact in their effects on adult neurogenesis. We examined neuronal recruitment in multiple telencephalic sites in adult male European starlings (Sturnus vulgaris) exposed to a factorial combination of flight exercise, dietary fatty acids and antioxidants. Experimental birds were flown in a wind tunnel following a training regime that mimicked the bird's natural flight behaviour. In addition to flight exercise, we manipulated the composition of dietary fatty acids and the level of enrichment with vitamin E, an antioxidant reported to enhance neuronal recruitment. We found that all three factors - flight exercise, fatty acid composition and vitamin E enrichment - regulate neuronal recruitment in a site-specific manner. We also found a robust interaction between flight training and vitamin E enrichment at multiple sites of neuronal recruitment. Specifically, flight training was found to enhance neuronal recruitment across the telencephalon, but only in birds fed a diet with a low level of vitamin E. Conversely, dietary enrichment with vitamin E upregulated neuronal recruitment, but only in birds not flown in the wind tunnel. These findings indicate conserved modulation of adult neurogenesis by exercise and diet across vertebrate taxa and indicate possible therapeutic interventions in disorders characterized by reduced adult neurogenesis.

Predators that have learned to associate warning coloration with toxicity often continue to include aposematic prey in their diet in order to gain the nutrients and energy that they contain. As body size is widely reported to correlate with energetic content, we predicted that prey size would affect predators' decisions to eat aposematic prey. We used a well-established system of wild-caught European starlings, Sturnus vulgaris, foraging on mealworms, Tenebrio molitor, to test how the size of undefended (water-injected) and defended (quinine-injected) prey, on different coloured backgrounds, affected birds’ decisions to eat defended prey. We found that birds ate fewer defended prey, and less quinine, when undefended prey were large compared with when they were small, but that the size of the defended prey had no effect on the numbers eaten. Consequently, we found no evidence that the mass of the defended prey or the overall mass of prey ingested affected the amount of toxin that a predator was willing to ingest, and instead the mass of undefended prey eaten was more important. This is a surprising finding, challenging the assumptions of state-dependent models of aposematism and mimicry, and highlighting the need to understand better the mechanisms of predator decision making. In addition, the birds did not learn to discriminate visually between defended and undefended prey based on size, but only on the basis of colour. This suggests that colour signals may be more salient to predators than size differences, allowing Batesian mimics to benefit from aposematic models even when they differ in size., Highlights • The size of toxic prey did not affect the amount of toxin ingested by birds. • Total prey mass eaten did not affect the amount of toxin ingested by birds. • The amount of toxin ingested by birds depended on the mass of nontoxic prey. • Colour signals may be more salient to predators than size differences. • Findings have implications for the selection pressures acting on aposematic prey.

The poultry red mite, Dermanyssus gallinae, is currently a significant pest in the poultry industry in Europe. Biological control by the introduction of predatory mites is one of the various options for controlling poultry red mites. Here, we present the first results of an attempt to identify potential predators by surveying the mite fauna of European starling (Sturnus vulgaris) nests, by assessing their ability to feed on poultry red mites and by testing for their inability to extract blood from bird hosts, i.e., newly hatched, young starlings and chickens. Two genuine predators of poultry red mites are identified: Hypoaspis aculeifer and Androlaelaps casalis. A review of the literature shows that some authors suspected the latter species to parasitize on the blood of birds and mammals, but they did not provide experimental evidence for these feeding habits and/or overlooked published evidence showing the reverse. We advocate careful analysis of the trophic structure of arthropods inhabiting bird nests as a basis for identifying candidate predators for control of poultry red mites.

Exposure to maternally derived glucocorticoids during embryonic development impacts offspring phenotype. Although many of these effects appear to be transiently ‘negative’, embryonic exposure to maternally derived stress hormones is hypothesized to induce preparative responses that increase survival prospects for offspring in low-quality environments; however, little is known about how maternal stress influences longer-term survival-related performance traits in free-living individuals. Using an experimental elevation of yolk corticosterone (embryonic signal of low maternal quality), we examined potential impacts of embryonic exposure to maternally derived stress on flight performance, wing loading, muscle morphology and muscle physiology in juvenile European starlings (Sturnus vulgaris). Here we report that fledglings exposed to experimentally increased corticosteronein ovoperformed better during flight performance trials than control fledglings. Consistent with differences in performance, individuals exposed to elevated embryonic corticosterone fledged with lower wing loading and had heavier and more functionally mature flight muscles compared with control fledglings. Our results indicate that the positive effects on a survival-related trait in response to embryonic exposure to maternally derived stress hormones may balance some of the associated negative developmental costs that have recently been reported. Moreover, if embryonic experience is a good predictor of the quality or risk of future environments, a preparative phenotype associated with exposure to apparently negative stimuli during development may be adaptive.

The first speculations about collective animal behaviour date back to the observations of Pliny on flocks of starlings (translated by Rackham 1933). His remarks were necessarily qualitative, although reasonable too. Most of the hypotheses formulated almost 2000 years later were based on equally qualitative observations (Selous, 1931 and Emlen, 1952). At times, the study of collective animal behaviour has been complemented by analogies with instances of collective behaviour in other fields of science, prominently physics (Radokov 1973). However, in the absence of any quantitative empirical insight, attempts to address the fundamental issues of collective behaviour rapidly became speculative.

Numerous studies have examined predation risk resulting from the costs of impaired flight performance associated with many key life-history stages such as reproduction and migration. Interestingly, although avian nestlings experience multiple resource-based physiological trade-offs and undergo considerable morphological and physiological changes during postnatal development, there is no data available on how nestlings manage the competing demands of growth and the development of flight ability at this critical life-history stage. We examined numerous morphological traits to determine which are responsible for variation in flight performance in juvenile European starlings (Sturnus vulgaris), a sexually size-dimorphic passerine. We then manipulated maternal quality during chick rearing (via feather clipping) to examine sex-specific sensitivity of fledgling flight performance to the quality of the rearing environment. Results suggest that the mechanics underlying variation in juvenile flight performance are relatively simple, being principally determined by the ratio of pectoral muscle mass to body mass (BM) and the surface area of the wings. Interestingly, although the maternal quality manipulation decreased BM and structural size in daughters, only the flight performance of sons was negatively affected. Our results suggest that a survival-related trait can be significantly affected in the larger sex when raised under stressful conditions. Furthermore, measuring only BM and structural size may not be sufficient in understanding how the sexes are affected by stressful rearing conditions in sexually size-dimorphic species. © The Author 2007. Published by Oxford University Press on behalf of the International Society for Behavioral Ecology. All rights reserved.

Animals can insure themselves against the risk of starvation associated with unpredictable food availability by storing energy reserves or gathering information about alternative food sources. The former strategy carries costs in terms of mass-dependent predation risk, while the latter trades off against foraging for food; both trade-offs may be influenced by an individual's developmental history. Here, we consider a possible role of early developmental experience in inducing different mass regulation and foraging strategies in European starlings. We measured the body mass, body condition, foraging effort, food consumption and contrafreeloading (foraging for food hidden in sand when equivalent food is freely available) of adult birds (≥10 months old) that had previously undergone a subtle early life manipulation of food competition (cross-fostering into the highest or lowest ranks in the brood size hierarchy when 2–12 days of age). We found that developmentally disadvantaged birds were fatter in adulthood and differed in foraging behaviour compared with their advantaged siblings. Disadvantaged birds were hyperphagic compared with advantaged birds, but only following a period of food deprivation, and also spent more time contrafreeloading. Advantaged birds experienced a trade-off between foraging success and time spent contrafreeloading, whereas disadvantaged birds faced no such trade-off, owing to their greater foraging efficiency. Thus, developmentally disadvantaged birds appeared to retain a phenotypic memory of increased nestling food competition, employing both energy storage and information-gathering insurance strategies to a greater extent than their advantaged siblings. Our results suggest that subtle early life disadvantage in the form of psychosocial stress and/or food insecurity can leave a lasting legacy on foraging behaviour and mass regulation even in the absence of food insufficiency during development or adulthood., Highlights • Starvation may be avoided by storing energy reserves or gathering information. • Developmental history could impact these foraging decisions. • Starlings disadvantaged in nestling competition were fatter in adulthood. • Developmentally disadvantaged birds foraged faster and contrafreeloaded more. • Early life stress has a lasting legacy on foraging behaviour and mass regulation.

Since Darwin, evolutionary biologists envisaged various hypotheses to explain the advantages for males to exhibit exaggerated secondary sexual traits, also known as ornaments. One of these hypotheses proposes that male ornaments may signal to the females the benefits they can get by mating, and that female preference for ornamented males is one of the main selecting forces explaining the evolution of secondary sexual traits. The evolutionary scenario becomes more complex if we consider that in many species males bear multiple ornaments. Why multiple ornaments should evolve? Why and how do females base their choice among different male traits? Different ornaments could signal different aspects of male quality (=benefits). For example, individual condition at different stages of male’s life may by reflected by the expression of different ornaments, or diverse ornaments could respond differently to a similar stress experienced during a male life-history event due, for example, to a different response to carry-over effects. Condition dependence of male ornaments has been supported by a large number of studies on sexual secondary traits, yet whether and how different stresses at different life-history stages affect the expression of multiple ornaments has been investigated in a more limited number of cases. In my PhD project I used a passerine bird, the European starling (Sturnus vulgaris), as a model species given that males bear multiple secondary sexual traits. In this species it has been shown that females prefer males with long throat feathers that have high UV reflectance, that produce a complex song and, although with less empirical support, with more brightly colours on the beak. During my PhD I attempted to investigate the mechanisms that underlie the expression of male ornaments by experimentally manipulating individual condition during two energy-demanding life-history events, i.e. during nestling development and during the post-juvenile moult. Male attractiveness was directly evaluated in a female choice experiment. The first experimental manipulation aimed at investigating the effect of an immune challenge on growth and physiological responses on nestlings that were naturally infested with ectoparasites (manuscript 1), and to assess the temporal pattern of their first- and second-year moult (manuscript 2). The second experimental manipulation was used to test the effect of removing the stress caused by the nest ectoparasites on parental investment during the incubation (manuscript 3), and on parent-offspring communication during the nestling stage (manuscript 4). I then examined the temporal pattern of the post-juvenile moult in males from ectoparasite-free and naturally infested nests (manuscript 5). A third experimental manipulation consisted of supplementing with or depriving of carotenoids the diet of males in the course of their post-juvenile moult. I further tested the effect of nest ectoparasites and diet i) on the preening activity of males during winter, i.e. from the end of the moult to the start of the breeding period (manuscript 6), ii) on the expression of male ornaments and iii) on female preference (manuscript 7). My results suggest that an early stress, i.e. endotoxin or ectoparasites, does not significantly affect the nestling growth. Nestlings whose immune system was challenged with an endotoxin (LPS) showed similar antioxidant capacity and oxidative damage to those measured on control nestlings, whereas hematocrit was higher in second-brood LPS-nestlings than controls. Nestlings in ectoparasite-free nests produced a more conspicuous postural begging than that produced by nestlings in naturally infested nests. Parents were also sensitive to nest ectoparasites because they increased the time spent at the nest during the incubation period, although the provisioning effort during the nestling period was not different among deparasitized and control broods. Moult was advanced in birds injected with LPS and in those grown without nest ectoparasites, as they were probably in better condition than their counterparts and could therefore anticipate such costly life-history event. Birds from ectoparasite-free nests moulted over a longer period than controls, whereas moult duration of LPS and control birds was similar. The supplement of carotenoids during moult resulted in an increase of time invested in preening their plumage a few months after the end of the moult, and showed an increased yellow colouration of the beak in the following breeding season. As result, males that were grown in ectoparasite-free nests and were supplemented with carotenoids during the following moult were preferred by females in the mate choice experiment. In conclusion, the results of my PhD project provided an experimental evidence of carry-over effects in starlings. Males that experienced different stresses during the early stages of their life were less attractive for the females in their first breeding season. While I found a different colouration of the beak among birds from ectoparasite-free and control nests, the throat feathers were of similar length and colouration. This difference in attractiveness could be due to song characteristics during mate choice tests. Any attempt to individually record male song unfortunately failed and the effect of early stresses on song could not be assessed directly. Despite this, the resulting female preference for males that experienced favourable juvenile conditions suggests that male ornaments are considered as a whole during mate choice, and their expression is probably influenced by carry-over effects. These findings seem therefore in agreement with the redundant signal hypothesis, which suggests that female integrate the information of all male ornaments to assess the mate quality.

Author(s): Homan, H. Jeffrey; Slowik, Anthony A.; Penry, Linda B.; Linz, George M.; Anderson, Wendy Anderson | Abstract: Managing European starlings with DRC-1339 near urban and suburban areas can lead to adverse publicity resulting from encounters by the public with dead and dying birds. Collectors could retrieve the birds, if the likely sites of mass mortalities were known. In December 2009, we radio tagged 50 starlings at 3 sites in central New Jersey and studied their movements and behavior. Two of the sites were ensconced in a mosaic of suburban and urban habitats, whereas the other was in a rural setting. The sites were selected from a list of agricultural producers that had requested assistance from the Wildlife Services program in New Jersey. Starlings using the rural study site showed strong site fidelity (x-bar = 78% of days tracked), stayed closer during daytime wanderings (x-bar = 2 km), and roosted onsite. In contrast, starlings in the urban-suburban mosaic showed less fidelity (x-bar’s = 10% and 36%), wandered farther (x-bar’s = 6 km and 4 km), and seldom roosted onsite. No study sites were visited by members from the other radio-tagged cohorts. Major roosts in the urban-suburban mosaic averaged 10 km (n = 4, SE = 1.4) from the study sites. We predict that most starlings will remain within 6 km of the site during daytime. Poisoned starlings may become lethargic and seek refuge in dense vegetation (e.g., evergreens) near the baited site. Birds g6 km from a bait site are probably on a direct bearing between the bait site and roosting site.

Sexual differentiation of the brain has traditionally been thought to be driven by gonadal hormones, particularly testosterone (T). Recent studies in songbirds and other species have indicated that non-gonadal sex steroids may also be important. For example, dehydroepiandrosterone (DHEA) - a sex steroid precursor that can be synthesized in the adrenal glands and/or brain - can be converted into active sex steroids, such as 17β-estradiol (E2), within the brain. Here, we examine plasma DHEA and E2 levels in wild developing European starlings (Sturnus vulgaris), from hatch (P0) to fledging (P20). Blood samples were collected from either the brachial vein (n = 143) or the jugular vein (n = 129). In songbirds, jugular plasma is enriched with neurally-synthesized steroids and, therefore, jugular plasma is an indirect measure of the neural steroidal milieu. Interestingly, brachial DHEA levels were higher in males than females at P4. In contrast, jugular DHEA levels were higher in females than males at P0 and P10. Brachial E2 levels were higher in males than females at P6. Surprisingly, jugular E2 levels were not high and showed no sex differences. Also, we calculated the difference between brachial and jugular steroid levels. At several ages, jugular steroid levels were lower than brachial levels, particularly in males, suggesting greater neural metabolism of circulating DHEA and E2 in males than females. At a few ages, jugular steroid levels were higher than brachial levels, suggesting neural secretion of DHEA or E2 into the general circulation. Taken together, these data suggest that DHEA may play a role in brain sexual differentiation in songbirds. © 2008 Elsevier Inc. All rights reserved.

Vegetation-height management is a potential method to reduce bird numbers at airports. Based on studies in Europe, researchers recommended vegetation heights around 25 cm; however, preliminary studies in the United States produced conflicting results regarding the effect of tall (18 to >25 cm) vegetation on bird numbers at airports. From 1999 to 2002, we compared birds and other wildlife use of 4 short-vegetation plots (mean maximum height of 15.6 cm ± 5.1 SE and visual obstruction reading of 4.6 ± 3.0 cm) and 4 tall-vegetation plots (mean maximum height of 26.9 ± 8.4 cm and visual obstruction reading of 10.0 ± 5.0 cm) in Ohio. We surveyed bird use of the plots 2 to 3 times/week and observed 6,191 birds in short-vegetation plots and 5,962 birds in tall-vegetation plots. We detected no difference between short-vegetation and tall-vegetation plots in the probability of avian use of the plots when evaluated as a binary response of presence and absence. Small mammal capture rates in 100 adjusted trap nights were 0.0 in short-vegetation plots and 0.3 in tall-vegetation plots. We found no difference in the number of deer observed in the plots during sunset and spotlighting counts. There was slightly greater insect biomass in tall than in short-vegetation plots. Mowing negatively affected small mammal use. The generalization that tall vegetation (18 to >25 cm) alone would reduce bird use of an airport is not supported by the results of this study. Further research on vegetation density, composition, palatability, and nutritional value is necessary to accommodate airfield requirements for habitat that is pleasing to the public and repellent to wildlife.

Changes in hormones can affect many types of learning in vertebrates. Adults experience fluctuations in a multitude of hormones over a temporal scale, from local, rapid action to more long-term, seasonal changes. Endocrine changes during development can affect behavioral outcomes in adulthood, but how learning is affected in adults by hormone fluctuations experienced during adulthood is less understood. Previous reports have implicated the sex steroid hormone estradiol (E2) in both male and female vertebrate cognitive functioning. Here, we examined the effects of E2 on auditory recognition and learning in male European starlings (Sturnus vulgaris). European starlings are photoperiodic, seasonally breeding songbirds that undergo different periods of reproductive activity according to annual changes in day length. We simulated these reproductive periods, specifically 1. photosensitivity, 2. photostimulation, and 3. photorefractoriness in captive birds by altering day length. During each period, we manipulated circulating E2 and examined multiple measures of learning. To manipulate circulating E2, we used subcutaneous implants containing either 17-β E2 and/or fadrozole (FAD), a highly specific aromatase inhibitor that suppresses E2 production in the body and the brain, and measured the latency for birds to learn and respond to short, male conspecific song segments (motifs). We report that photostimulated birds given E2 had higher response rates and responded with better accuracy than those given saline controls or FAD. Conversely, photosensitive, animals treated with E2 responded with less accuracy than those given FAD. These results demonstrate how circulating E2 and photoperiod can interact to shape auditory recognition and learning in adults, driving it in opposite directions in different states.

The cattle feedlot affords an ideal habitat for large concentrations of birds. Several species are primarily involved in feed depredations and contamination. The development of an integrated systems approach to control involves the interaction of human attitude, cultural control practices and application of bird damage control techniques, each of which is a dynamic system in itself.

Each winter, more than 300 million blackbirds and starlings congregate in hundreds of roosting sites in the southeastern United States. In addition to nuisance problems involving odor and property damage from fecal material, and potential airport hazards, research studies to date suggest that the major problems with these birds and their roosts involve grain losses in feedlots, latent disease transmission to livestock, and public health concerns with histoplasmosis. Control methods development studies have shown the utility of Starlicide and nonchemical control methods in reducing starling feedlot problems. A sprinkler-irrigation delivery system for the surfactant, PA-14, has been developed that enhances its usefulness for lethal roost management. Research is being continued to (1) define the behavior and impact of roosting birds on the livestock industry, (2) improve methods of dispersing birds from roost sites, and (3) determine the effect of lethal roost control on subsequent roosting and foraging bird populations.

A brief history of the development of the winegrape industry in Monterey County, California is provided. In the early 1960s, several established wineries pioneered the initial premium varietal vineyards in the county, with very successful results. The early 1970s brought a grape planting boom: acreage jumped from 2,000 to over 37,000 acres in approximately 4 years. While a few of the early vineyards had suffered damage from starlings and linnets, the increased acreage brought increasingly significant bird damage problems. It was recognized that a county-wide bird damage control program needed to be developed, but there was little information on current effective methods, damage assessment, or costs of control methods. The county Agricultural Department assisted by instituting grower assessments to provide funds to hire local personnel, who would coordinate our efforts to apply and evaluate damage control methods. Currently, we have what we believe is the beginning of an effective program that utilizes bird traps, bait trays, and sound-scaring technologies. The program provides important communication among growers, in addition to timely sharing and implementation of tools and techniques. We believe that academic institutions need to be more directly involved with the growing animal damage problem at a field level, and to recognize the inadequacy of current research efforts.

Vineyard losses to birds are primarily due to two species; these are the starling (Sturnus vulgaris) and the house finch (Carpodacus mexicanus). The majority of losses in the Central California Coastal region are caused by the starling, due to the large numbers of migratory birds arriving prior to harvest. Starlings are best controlled by a combination of pyrotechnic and acoustic devices. Linnets are most effectively controlled by trapping and poisoning. No matter what type of control is used, it is necessary to have sound knowledge of the birds' behavior and reliable personnel carrying out the program. An effectively run program can reduce losses by as much as ninety percent.

Breeding populations of nuisance bird species were related to various types, designs, and quality of building construction in Columbia, Maryland. Since there were differences in the various parts of this new, planned city in types, builders, and architectural designs, it affords an excellent opportunity to study the effect these factors have on bird populations. Breeding starlings (Sturnus vulgaris), house sparrows (Passer domesticus), and pigeons (Columba livia) were unevenly distributed throughout the city, being concentrated in those specific areas with buildings having design or quality features that were favorable to these species. Specific examples of building designs and/or flaws in construction that created nuisance bird problems are described. Nuisance bird problems in newly constructed urban areas can be avoided by not using building designs that favor these birds and by preventing construction flaws that afford nuisance bird habitat.

Research efforts to combat the problem of European starling damage in livestock feeding areas (feedlots) by developing appropriate toxicants and stupefacients are described. Of about 500 chemicals screened for possible utility, 4 compounds showed promise at potential toxicants for further development and testing: TEPP (tetraethyl pyrophosphate), DRC-632 (0-[4-(methylthio-m-tolyl] phosphorothioate)), DRC-1327 (4-aminopyridine), and DRC-1339 (3-chloro-p-toluidine hydrochloride). TEPP was found to be too toxic to mammals to further develop its potential use against starlings. However, because it causes rapid death, it was useful in subsequent tests of bait acceptance by various avian species. DRC-632 was the first material noted to be far more toxic to birds than to mammals. Dermal toxicity proved more important than oral toxicity, but its extreme secondary hazard, especially to avian predators and scavengers, made it generally unsuitable for use. DRC-1327 was found to cause birds to emit distress cries and violent reactions in birds ingesting the materials, which often died, but also causing flocks to abandon the treated area. Field trials showed promise, and when bait acceptance by starlings is poor or fair, it is more effective than other known toxicants in reducing damage. DRCC-1339 (Starlicide) is the most selective bird toxicant presently known, providing starling control that is virtually nonhazardous to other animals. Discussions of bait materials and formulation, active ingredient dilutions, and baiting methods are provided.

Increasing problems caused by European starlings are described as their population has increased in the Pacific Northwest, causing significant damage in livestock feeding facilities, to fruit crops, and to ornamental holly groves. Starling biology and reproduction is discussed. Experimental methods to reduce damage are described in detail, including use of cage traps and light traps, and development of an avicide using thallium sulphate as the active ingredient.

The author discusses the concept of controlling pest animals, primarily birds, using sound as a tool to frighten birds from a specific location, or to deter bird damage. He notes that bio-acoustic sounds that have specific meaning, such as distress calls and alarm calls, often are more effective than sounds that simply are loud, but often are species-specific in effect. However, they do not need to be broadcast at high volume and thus are less objectionable to people within hearing range. Quality, timing, and strategies for the use of bio-acoustic sounds are discussed with many examples from attempts to use these against various bird species, especially European starlings. Reasons for lack of interest in research and commercialization of bio-acoustic sounds for bird control, in North America in particular, are discussed.