RESUMO
Nest material kleptoparasitism likely evolved in birds to reduce the cost of searching for and collecting material themselves. Although nest material kleptoparasitism has been reported commonly in colonially nesting species, reports for solitary breeding species are infrequent, especially for neotropical migratory species. Here, we report potential and actual nest material kleptoparasitism in the Worm-eating Warbler (Helmitheros vermivorum). We deployed video camera systems at passerine nests (n = 81) in east-central Arkansas during summers 2011-2012. In one video, we observed a Worm-eating Warbler stealing nesting material from a Hooded Warbler (Setophaga citrina) nest. One day later, we later observed a Worm-eating Warbler landing within 0.5 m of the same warbler nest when the female was incubating, which possibly deterred a second theft of nesting material. In a third video recording, we observed another Worm-eating Warbler landing within 1 m of an Indigo Bunting (Passerina cyanea) nest. As far as we could determine, neither of these latter two nest visits resulted in nest material kleptoparasitism. Potential benefits of nest material kleptoparasitism include reduced competition for limited nest materials, easy access to suitable material, reduced travel distance, and reduction of nest predation risk; however, costs include risk of attack by host or introducing parasites to one's nest. Importantly, this behavior could ultimately affect the behavioral and life history evolution of a species. We suggest further work should be conducted to determine the prevalence of nest material kleptoparasitism in Worm-eating Warblers and other solitary breeding passerines, including efforts to quantify the benefits and costs of this behavior.
RESUMO
Woodpeckers can be difficult to detect, as they are often cryptic, secretive, occurring in low densities, and wary of humans. Several methods exist to detect woodpeckers (e.g., playback surveys, passive point counts), yet no research has established which technique best detects these elusive picids. Thus, we designed an experiment to determine which of three methods best results in a detection of Magellanic Woodpeckers (Campephilus magellanicus), and if weather variables influence detection probability.Mostly during austral summers 2015-2017, we (a) used a drumming device to simulate a double-knock (i.e., territorial acoustical signal), (b) broadcasted a territorial call, and (c) passively listened (control) for Magellanic Woodpeckers. We conducted our experiment on Navarino Island, Chile, where the Magellanic Woodpecker is the sole picid.The drumming device most effectively influenced the likelihood of a woodpecker detection. The odds of a woodpecker responding to a double-knock were 2.14 times more likely than responding to either a call or control. Moreover, the odds of a woodpecker detection decreased by 42% as wind increased by one category and decreased by 40% for every additional month (i.e., October-March), which was expected because woodpeckers become less territorial as the breeding season progresses.As Campephilus woodpeckers communicate via drums or double-knocks, using a drumming device likely will be an effective technique to detect not only Magellanic Woodpeckers, but other woodpeckers within the Campephilus genus in Central and South America.