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In resident Amazonian mixed-species flocks, the pattern of attraction of transient species to nuclear Dusky-throated Antshrikes (Thamnomancs ardesiacus) and Long-winged Antwrens (Myrmotherula longipennis) and the pattern of heterospecific attraction between the nuclear species are undocumented. Patterns of attraction can help elucidate the nature of interspecific relationships (i.e., whether they are mutualistic, commensal, or parasitic). We played Dusky-throated Antshrike and Long-winged Antwren vocalizations to flocks and recorded how many transient species approached the playbacks, whether the antshrikes and antwrens were attracted to each other's playbacks, and how strongly they responded to the playbacks. More transient species were attracted to the antshrike vocalizations than antwren vocalizations, and more transient species were attracted to antwren than control vocalizations. Dusky-throated Antshrikes and Long-winged Antwrens approached each other's playback significantly more often than they approached control playbacks; the antwrens responded significantly more strongly to antshrike vocalizations than the antshrikes did to antwren vocalizations. Species may be more attracted to Dusky-throated Antshrikes because of their reliable alarm calling, whereas species may be attracted to antwrens because they serve as a flock indicator. Finally, Dusky-throated Antshrikes and Long-winged Antwrens likely confer benefits to each other, but those benefits may not be symmetrical. Received 7 August 2016. Accepted 3 March 2017. Key words: antbirds, interspecific interactions, mutualism, Neotropical, playback, Thamnophilidae. En bandadas mixtas que viven en Amazonia, la pauta de attracción de especies transitorios y especies centros, como los Thamnomanes ardesiacus y Myrmotherula longipennis, y la pauta de attracción entre los especies centros no son documentados. Pautas de attraccion puede elucidar el índole de las relaciones entre especies diferentes (como mutualismo, comensalismo, o parasitismo). Tocamos vocalizaciones de T. ardesiacus y M. longipennis a bandadas mixtas y recordamos el numero de especies que acercaron, si T. ardesiacus y M. longipennis se atrajeron a sus vocalizaciones, y la fuerza de atracción. Más especies transitorios se atrataron a las vocalizaciones del T. ardesiacus que el M longipennis, y más especies transitorios de atrataron a las vocalizaciones del M. longipennis que el control cientifico. T. ardesiacus y M. longipennis acercaron las vocalizaciones del otro más que ellos acercaron la vocalizacion del control; el M. longipennis respondió con mas fuerza a las vocalizaciones del T. ardesiacus que el T. ardesiacus respondió a las vocalizaciones del M. longipennis. Es possible que los especies son más atraidos al T. ardesiacus porque el T. ardesiacus hace vocalizaciones alarmas cuando hay un depredador. Al fin, el T. ardesiacus y el M. longipennis probablemente conficron beneficios al otro, pero los beneficios son asimétricos. Palabras clave: hormigueros, intcraccines interespecíficas, mutualismo, Neotropical, reproducción dc vocalizaciones, Thamnophilidae., Hundreds of species worldwide participate in mixed-species flocks, defined as [greater than or equal to]2 species moving together for [greater than or equal to]5 min without a concentrated feeding source [...]

Some fruit-eating bird species commonly consume cultivated fruit. Species-specific variation in diet preferences could result in varying use of orchards and impacts on the fruit-producing industry. However, species-specific studies of avian orchard use are lacking, particularly throughout the fruit-growing season. Our objectives were to quantify the frequency of daily bird visits to orchards and the amount of time birds spent visiting orchards each day over the fruit-ripening season. Birds are well-documented consumers of cultivated sweet cherries (Prunus avium), which are relatively high in sugar and low in proteins and lipids. American Robins (Turdus migratorius) and Cedar Waxwings (Bombycilla cedrorum) are common fruit-consumers in sweet cherry orchards. Robins often consume larger proportions of invertebrates and prefer lipid-rich fruits, while waxwings choose sugary fruits. Given these species-specific diet differences, we hypothesized waxwings would spend a greater proportion of days and more time each day in cherry orchards, compared to robins. We used radio telemetry to track the habitat use of 25 American Robins and 17 Cedar Waxwings in sweet cherry orchards of Michigan. Over their respective radio-tracking periods, waxwings visited orchards a greater percentage of days than robins (waxwings: mean = 21%, SD = 22; robins: mean = 6%, SD = 4). In addition, waxwings visited orchards for more time each day. Differences in diet preferences and nutritional physiology may translate into species-specific patterns of habitat use for birds in fruit-rich environments. Received 4 February 2015. Accepted 2 August 2015. Key words: American Robin, Cedar Waxwing, cherry, foraging, habitat use, orchard, telemetry., Animals are expected to forage where and when they can obtain sufficient accessible and nutritious foods (Hengeveld et al. 2009). Orchards offer rich patches of foraging habitat with abundant food [...]

We monitored nesting attempts of White-throated (Turdus assimilis) and Clay-colored thrushes (T. grayi) over 4 years in southern Costa Rica to compare nest success in recently abandoned coffee (Coffea spp.) plantations, pasture, and along roads. Daily mortality rates of Clay-colored Thrush nests were lower in pasture (0.054 [+ or -] 0.014) than abandoned coffee plantations (0.096 [+ or -] 0.012). Daily mortality rates of White-throated Thrush nests were not influenced by land-cover type but were lower at highly concealed nests (0.058 [+ or -] 0.005) compared to less concealed nests (0.090 [+ or - ]0.017), and at nests that were on the ground (0.0580 [+ or -] 0.005) versus in vegetation (0.076 [+ or -] 0.007). Daily mortality rates for nests of both species were very low at an active coffee plantation where nests were monitored in 1 year (0.006 [+ or -] 0.004 and 0.015 [+ or -] 0.015, for White-throated and Clay-colored thrushes, respectively). Nests at the active plantation were heavily concealed which, along with results for White-throated Thrushes in abandoned coffee, indicates concealment has a strong influence on tropical thrush nest success. Nest success appears to be heavily dependent on factors that may influence both concealment and or habitat for predators. Nest success also appears to be strongly site-specific, making it difficult to provide general statements about the conservation value of different land-cover types. Received 22 September 2010. Accepted 9 February 2011., An estimated 50% of what was once tropical forest has been cleared (Wright 2005). The agricultural land-cover types that replace tropical forest will influence future population sizes and fates of [...]

Tropical birds may differ from temperate birds in their sensitivity to forest edges. We provide predictions about the proportions of tropical and temperate species that should avoid or exploit edges, and relationships between natural-history characters and edge responses. We conducted exploratory meta-analyses from 11 studies using 287 records of 220 neotropical and temperate species' responses to edges to address our predictions. A higher proportion of neotropical species were edge-avoiders compared with temperate species and a higher proportion of temperate species were edge-exploiters compared with neotropical species. Edge-avoiding responses were positively associated with being an insectivore for neotropical birds, and with being of small body mass and a latitudinal migrant for temperate birds. Temperate edge-exploiters were less likely to be insectivores and migrants than temperate birds that were not edge-exploiters. A greater proportion of neotropical birds than temperate birds may be at risk from forest fragmentation if edge-avoidance is a reasonable indicator of an inability to adapt to land-cover change. Future progress in our understanding of forest bird responses to edges is dependent upon greater standardization of methods and designing studies in the context of recent theoretical developments., The conversion of forest to other land-cover types leads to creation of edges (Murcia 1995). Species' responses to land-cover change and edge creation in temperate forests may not be generalizable [...]

We document characteristics of the previously undescribed nest, nest site, and eggs of the Ochre-breasted Antpitta (Grallaricula flavirostris). We found three nests in 1999 and 2000 in the Talamanca Mountains of southern Costa Rica. The nests were cup shaped and constructed primarily of green moss with linings of thin sticks and black rhizomorphs. Mean nest height above the ground was 3.1 m. Nests were located in the forks of slim saplings in two eases and, in one case, in a larger tree at a point where several smaller branches left the trunk. We observed clutches of one and two eggs. Eggs appeared pale reddish brown with some darker spotting. The incubation period was 17-21 d and we estimate the nestling period lasts 14-16 d., Many aspects of the biology of most antpittas (Formicariidae) are not well understood because the birds are easily overlooked and relatively difficult to observe (Robbins et al. 1994), with new [...]