Juvenile Survival in a Neotropical Migratory Songbird Is Lower than Expected

Abstract

Attempts to estimate and identify factors influencing first-year survival in passerines, survival between fledging and the first reproductive attempt (i.e. juvenile survival), have largely been confounded by natal dispersal, particularly in long-distance migratory passerines. We studied Prothonotary Warblers (Protonotaria citrea) breeding in nest boxes to estimate first-year survival while accounting for biases related to dispersal that are common in mark-recapture studies. The natal dispersal distribution (median = 1420 m; n = 429) and a distance-dependent recruitment rate, which controls for effects of study site configuration, both indicated a pattern of short-distance natal dispersal. This pattern was consistent with results of a systematic survey for birds returning outside the nest box study sites (up to 30 km in all directions) within a majority (81%) of total available bottomland forest habitat, further suggesting that permanent emigration outside of the study system was rare. We used multistate mark-recapture modeling to estimate first-year survival and incorporated factors thought to influence survival while accounting for the potential confounding effects of dispersal on recapture probabilities for warblers that fledged during 2004–2009 (n = 6093). Overall, the average first-year survival for warblers reared without cowbird nestmates was 0.11 (95% CI = 0.09–0.13), decreased with fledging date (0.22 early to 0.03 late) and averaged 40% lower for warblers reared with a brood parasite nestmate. First-year survival was less than half of the rate thought to represent population replacement in migratory passerines (∼0.30). This very low rate suggests that surviving the first year of life for many Neotropical migratory species is even more difficult than previously thought, forcing us to rethink estimates used in population models.

The first 50 years of the North American Breeding Bird Survey

“…For instance, because adult birds are typically considered highly philopatric (e.g., Greenwood andHarvey 1982, Holmes and, natal dispersal distances will often determine distances between interacting sites of population sources and population sinks. A few previous studies have found correlations in the abundance of passerine birds from one year to the next in areas 2-100 km apart, which is evidence of source-sink dynamics at this spatial scale (Winkler et al 2005, Tittler et al 2006, McKim-Louder et al 2013). However, the geographic scales at which source-sink dynamics operate in avian ecology remain poorly understood.…”

Demographic response of a shrubland bird to habitat creation, succession, and disturbance in a dynamic landscape

“…High site fidelity for adult shrubland birds has been shown to occur even in landscapes where suitable habitat is less clustered than it is in our site (Holmes and Sherry, 1992;Lehnen and Rodewald, 2009). One reason for our relatively high natal return rates could be because of the large number of locally suitable territories for prairie warblers in our compact study area in relation to the surrounding landscape, allowing us to detect birds that survived and returned at a local scale (Fajardo et al, 2009;McKim-Louder et al, 2013). Nevertheless, the study site was not completely isolated; multiple power line corridors and other early-successional habitats within 5 km of the study site provided suitable prairie warbler habitat that held territorial singing males.…”

Age-specific survival of male Golden-cheeked Warblers on the Fort Hood Military Reservation, Texas

“…Thus, it is not surprising that our estimated HY Φ is no different than previous HY Φ estimates when taking into account the approximate 95% confidence interval, i.e., the SE of ±0.06. All three of these HY Φ estimates are well above the HY Φ mean ± SE estimates reported for Prothonotary Warblers, which are 0.06 ± 0.01 and 0.11 ± 0.01, with and without cowbird nestmates, respectively (McKim-Louder et al 2013). However, Φ estimates are not directly comparable between studies.…”

“…However, Φ estimates are not directly comparable between studies. McKim-Louder et al (2013) banded young in nest boxes before fledging occurred and had both males and females in their analysis, and Φ for HY birds can be related to an assortment of factors including differences in dispersal patterns among species and/or subpopulations. We currently do not have the data to assess whether the relatively high HY GCWA Φ estimates are an artifact of the individual study plot, are an outcome of the sampling protocol used to band individuals, or are reasonable for this particular species.…”