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Understanding the factors that drive spatial synchrony among populations or species is important for management and recovery of populations. The range‐wide declines in Atlantic salmon (Salmo salar) populations may be the result of broad‐scale changes in the marine environment. Salmon undergo rapid growth in the ocean; therefore changing marine conditions may affect body size and fecundity estimates used to evaluate whether stock reference points are met. Using a dataset that spanned five decades, 172,268 individuals, and 19 rivers throughout Eastern Canada, we investigated the occurrence of spatial synchrony in changes in the body size of returning wild adult Atlantic salmon. Body size was then related to conditions in the marine environment (i.e., climate indices, thermal habitat availability, food availability, density‐dependence, and fisheries exploitation rates) that may act on all populations during the ocean feeding phase of their life cycle. Body size increased during the 1980s and 1990s for salmon that returned to rivers after one (1SW) or two winters at sea (2SW); however, significant changes were only observed for 1SW and/or 2SW in some mid‐latitude and northern rivers (10/13 rivers with 10 of more years of data during these decades) and not in southern rivers (0/2), suggesting weak spatial synchrony across Eastern Canada. For 1SW salmon in nine rivers, body size was longer when fisheries exploitation rates were lower. For 2SW salmon, body size was longer when suitable thermal habitat was more abundant (significant for 3/8 rivers) and the Atlantic Multidecadal Oscillation was higher (i.e., warmer sea surface temperatures; significant for 4/8 rivers). Overall, the weak spatial synchrony and variable effects of covariates on body size across rivers suggest that changes in Atlantic salmon body size may not be solely driven by shared conditions in the marine environment. Regardless, body size changes may have consequences for population management and recovery through the relationship between size and fecundity. [ABSTRACT FROM AUTHOR]

Swallow (Family: Hirundinidae) populations in the Canadian Maritimes have declined since the 1980s. Using mark–recapture data from 2012 to 2019, we determined apparent annual adult survival rates for Barn (Hirundo rustica Linnaeus, 1758), Tree (Tachycineta bicolor (Vieillot, 1808)), Bank (Riparia riparia (Linnaeus, 1758)), and Cliff (Petrochelidon pyrrhonota (Vieillot, 1817)) swallows. For two data-rich species (Barn and Tree swallows), we modelled the relationships between survival and weather (cold snaps, precipitation, temperature, and wind speed), climate (El Niño–Southern Oscillation (ENSO) and North Atlantic Oscillation (NAO)), Enhanced Vegetation Index (EVI) as a measure of primary productivity during the winter, number of active nests as a measure of site quality, and the Breeding Bird Survey (BBS) annual population index as density-dependent processes. Survival rates for all four species were typically higher (Barn and Tree) or similar to (Cliff and Bank) of estimates from populations that have not undergone severe, long-term declines. Across weather and climate variables, conditions that are typically favourable for high insect availability (e.g., higher precipitation, warmer temperatures, and lower wind speeds) resulted in higher survival. For female Barn and Tree swallows, survival was higher when EVI was lower, and for Barn Swallows, survival was also higher when the BBS index was higher. Collectively our results demonstrate that conditions throughout the annual cycle affect survival, and the relationships with weather and climate variables support the importance of high insect availability. [ABSTRACT FROM AUTHOR]

Carryover effects occur when an individual's experience during one stage of the annual cycle influences their behaviour in subsequent stages. This includes stages of the annual cycle, such as migration, when behaviour, such as departure timing, is also affected by circannual and circadian cues. In birds, the initiation of autumn migratory movements is often related to the timing of the cessation of the breeding season. However, less is known as to whether breeding season carryover effects also affect the pace of migration. To determine whether there are carryover effects from the breeding season to migration in barn swallows, Hirundo rustica , we monitored nests and used the Motus Wildlife Tracking System to determine migratory departure dates and the pace of migration. Barn swallows that finished breeding later in the summer initiated migration later and migrated faster through North America than swallows that finished breeding earlier in the summer. However, daily flight speeds were unrelated to the timing of the breeding season, suggesting that late-departing individuals increased their overall pace by reducing stopovers. Our results suggest that although barn swallows do not establish a nonbreeding territory, there are constraints during migration that require late-departing individuals to compensate for carryover effects from the breeding season. Late departure is not necessarily disadvantageous if individuals are able to 'catch-up' to early-departing individuals, but more work is needed to assess whether late departure and the faster pace of migration affect the subsequent survival of these individuals. • We examined whether departure timing affects barn swallows' pace of autumn migration. • Daily flight speeds during migration were unrelated to departure timing. • Late-breeding birds migrated later but also migrated faster by reducing stopovers. [ABSTRACT FROM AUTHOR]

When an environmental cue that previously signaled a suitable habitat leads an animal to use an unsuitable site, individual fitness can decrease, ultimately leading to population declines. Such "ecological traps" may be particularly likely for birds that use human infrastructure for nesting. Here we tested whether high nest temperatures and the physical properties of barns are associated with lower breeding success for a declining population of Cliff Swallows (Petrochelidon pyrrhonota (Vieillot, 1817)). We monitored nests under barn eaves below wood and metal roofs to determine nestling survival and mass, and recorded temperature under barn eaves, to relate ambient temperature to eave temperature. We found that eave temperature increased with ambient temperatures and was higher at high temperatures and lower at cool temperatures under metal roofs than wood roofs. Nestling survival was lower during periods with higher ambient temperatures, and both survival and mass were lower under metal roofs. Our findings suggest that barn eaves, especially those with metal roofs, may be an ecological trap for Cliff Swallows, where a seemingly suitable nesting site early in the breeding season results in low breeding success. Furthermore, warming temperatures may lead to ecological traps for other bird species, particularly those nesting in man-made structures. [ABSTRACT FROM AUTHOR]

The article discusses valuable contributions to our understanding of factors potentially affecting aerial insectivorous bird populations. Most of the papers in this collection were presented as part of the symposium. Topics include the diversity of stressors potentially contributing to aerial insectivore declines at multiple scales and during different parts of the annual cycle.

Piping Plovers (Charadrius m. melo-dus) were banded in eastern Canada, in the Gulf of St. Lawrence (Gulf) region, including the Magdalen Islands (Quebec), New Brunswick, Newfoundland, northern Nova Scotia and Prince Edward Island, and the southern Nova Scotia (sNS) region from 1998-2003, and recaptured and/or resighted from 1999-2007. Return rates of banded individuals were greater for adults than juvenile birds, likely reflecting the higher survival and site fidelity of this age class. The best-fit model explaining differences in annual dispersal distance included age class (P < 0.001), region (P = 0.004) and the interaction of age class and region (P = 0.074). Juvenile dispersal movements in the Gulf (median: 28.0 km, range: 0.4-306.3 km) were greater than in sNS (median: 18.6 km, range: 6.5-74.8 km), but adult movements in sNS (median: 4.0 km, range: 0.01-70.7 km) were greater than in the Gulf (median: 0.5 km, range: 0.01-298.6 km). While some annual dispersal movements in the Gulf were large enough to cover the distance between both regions (>225 km), these movements only represented 1% of all observations and none involved movements between the Gulf and sNS. The lack of movement between regions, and previous studies documenting differences in population dynamics and habitat use, suggests that two distinct breeding populations of Piping Plovers exist in eastern Canada. Future management of the species should consider the distinct conservation needs of both populations and recognize that local efforts may not result in regional population increases because of small dispersal distances in eastern Canada, and, potentially, in other populations in North America. At this time, the small sNS population may be particularly vulnerable to extirpation, as the potential for dispersal from nearby populations appears limited. [ABSTRACT FROM AUTHOR]

Carry-over effects from one stage of the annual cycle to subsequent stages can have profound effects on individual fitness. In migratory birds, much research has been devoted to examining such effects from the nonbreeding to the breeding period. We investigated potential carry-over effects influencing spring body condition, breeding phenology, and performance for 3 species of sympatric, declining Nearctic–Neotropical migratory swallows: Bank Swallow (Riparia riparia), Barn Swallow (Hirundo rustica), and Cliff Swallow (Petrochelidon pyrrhonota). To examine carry-over effects, we used structural equation modeling and several intrinsic markers, including stable isotope (δ 2H, δ 13C, and δ 15N) and corticosterone (CORTf) values from winter molted-feathers, and changes in telomere length between breeding seasons. We found support for carry-over effects for all 3 species, however, the specific relationships varied between species and sexes. Effects leading to lower breeding performance were only observed in male Bank, female Barn, and female and male Cliff Swallows. In most cases, carry-over effects were attributed to differences in stable isotope values (most commonly with δ 2H) presumably related to differences in winter habitat use, but, for Cliff Swallows, negative carry-over effects were also linked to higher CORTf values and greater rates of telomere shortening. This work provides further support for the potential role of nonbreeding conditions on population declines, and indicates how multiple intrinsic markers can be used to provide information on ecological conditions throughout the annual cycle. [ABSTRACT FROM AUTHOR]

Migratory connectivity is the degree to which populations are linked in space and time across the annual cycle. Low connectivity indicates mixing of populations while high connectivity indicates population separation in space or time. High migratory connectivity makes individual populations susceptible to local environmental conditions; therefore, evaluating migratory connectivity continuously across a species range is important for understanding differential population trends and revealing places and times contributing to these differences. The common nighthawk Chordeiles minor is a widespread, declining, long‐distance migratory bird. Variable population trends across the nighthawk breeding range suggest that knowledge of migratory connectivity is needed to direct conservation. We used GPS tags to track 52 individuals from 12 breeding populations. We estimated migratory connectivity as 0.29 (Mantel coefficient: 0 = no connectivity, 1 = full connectivity) between the breeding and wintering grounds. We then estimated migratory connectivity at every latitude (spatial connectivity) or day (temporal connectivity) of migration and smoothed those migratory connectivity estimates to produce continuous migratory connectivity 'profiles'. Spatial and temporal connectivity were highest during migration through North America (around 0.3–0.6), with values generally around 0 in Central and South America due to mixing of populations along a common migratory route and similar migration timing across populations. We found local peaks in spatial and temporal connectivity during migration associated with crossing the Gulf of Mexico. We used simulations to estimate the probability that our method missed peaks (spatial: 0.12, temporal: 0.18) or detected false peaks (spatial: 0.11, temporal: 0.37) due to data gaps and showed that our approach remains useful even for sparse and/or sporadic location data. Our study presents a generalizable approach to evaluating migratory connectivity across the full annual cycle that can be used to focus migratory bird conservation towards places and times of the annual cycle where populations are more likely to be limited. [ABSTRACT FROM AUTHOR]

Background: The Loggerhead Shrike, Eastern subspecies (Lanius ludovicianus ssp.) (LOSH) is a predatory songbird native to Eastern North America. It is estimated that there are fewer than 55 breeding pairs of this subspecies in North America. Captive breeding plays a critical role in preventing the extirpation of this subspecies from its Canadian range. Unfortunately, high numbers of unexplained deaths among young birds in the captive breeding population threatened the success of this program. This paper describes fledgling mortality in the captive breeding population, and seeks to identify factors associated with fledgling survival and, ultimately, to identify steps to mitigate fledgling mortality. Results: Over the study period (2006-2011) at two breeding sites, 696 LOSH were fledged. Among these, 68 % (n = 474) were released, 10 % (n = 69) were retained in the captive breeding population, and 22 % (n = 155) died. Fledgling survival declined from 99 % in 2006 to 44 % in 2011. The odds of survival were significantly lower for fledglings that were part of a second clutch. As the number of fledglings in a clutch increased, the odds of surviving increased significantly. As the breeding female aged from one to four years of age, there was a marked increase in the odds of a fledgling surviving, which then subsequently declined as females aged further. Conclusions: Based on our analyses, clutch number (first or second), number of fledglings in the brood, and age of breeding females were significant predictors of fledgling survival. Long-term breeding management decisions will have to balance the need to increase the number of individuals and breeding pairs in the wild by releasing large numbers of young, against the need to maintain a genetically viable captive population, until the wild population is large enough to be self-sustaining. [ABSTRACT FROM AUTHOR]