Migratory species can experience limiting factors at different locations and during different periods of their annual cycle. In migratory birds, these factors may even occur in different hemispheres. Therefore, identifying the distribution of populations throughout their annual cycle (i.e., migratory connectivity) can reveal the complex ecological and evolutionary relationships that link species and ecosystems across the globe and illuminate where and how limiting factors influence population trends. A growing body of literature continues to identify species that exhibit weak connectivity wherein individuals from distinct breeding areas co-occur during the nonbreeding period. A detailed account of a broadly distributed species exhibiting strong migratory connectivity in which nonbreeding isolation of populations is associated with differential population trends remains undescribed. Here, we present a range-wide assessment of the nonbreeding distribution and migratory connectivity of two broadly dispersed Nearctic-Neotropical migratory songbirds. We used geolocators to track the movements of 70 warblers from sites spanning their breeding distribution in eastern North America and identified links between breeding populations and nonbreeding areas. Unlike blue-winged warblers (), breeding populations of golden-winged warblers () exhibited strong migratory connectivity, which was associated with historical trends in breeding populations: stable for populations that winter in Central America and declining for those that winter in northern South America.

The decline of piping plover (Charadrius melodus) populations and subsequent listing as a threatened species has been attributed, in part, to low chick survival. During 1988-90, we observed piping plover chicks daily to evaluate hypotheses of differential food resources, predation, and disturbance explaining differences in chick survival in 3 habitats on Assateague Island National Seashore (AINS), Maryland. Chicks reared on the bay beach and island interior had higher daily survival rates (0.97, 0.99 vs. 0.87; P < 0.001), higher foraging rates (13.3, 10.8 vs. 5.9 attemptsjmin; P < 0.001), and spent more time foraging (76, 80 vs. 37%, P < 0.004) than chicks reared on the ocean beach. Terrestrial arthropod abundance on the bay beach and island interior was greater than on the ocean beach in 5 of 6 cases (P :s 0.01). Amphipods, however, were more abundant on ocean beaches than in bay and island interior habitats each year (P :S 0.03). Chicks 4-5 days old that were reared on the bay beach or island interior habitats were heavier than those reared on the ocean beach (8.5, 7.8 vs. 6.5 g; P < 0.01). Overall disturbance rates did not differ among habitats (behavioral observations; P = 0.29). The number of predator trails did not differ among the 3 habitats (P = 0.2). Red fox (Vulpes wipes) trails were more numerous in the island interior and ocean beach (P < 0.001), ghost crab (Ocypode quadrata) burrows were more numerous on ocean beach (P < 0.001), and gull (Larus spp.) and raccoon (Procyon rotor) trails were more numerous on bay beach (P < 0.001 and P = 0.001, respectively). Piping plover chicks moved from ocean beach nest sites to the bay beach and island interior along ephemeral, vegetation-free paths created during winter storms by waves surging across the island. These paths should be maintained to enable piping plover chicks to move to the island interior and bay habitats where chick survival is greatest. Preserving access to high quality brood-rearing habitat will ensure reproductive rates that will sustain the local population and contribute to the species' recovery.

Studies of songbird breeding habitat often compare habitat characteristics of used and unused areas. Although there is usually meticulous effort to precisely and consistently measure habitat characteristics, accuracy of methods for estimating which areas are used versus which are unused by birds remains generally untested. To examine accuracy of spot‐mapping to identify singing territories of golden‐winged warblers (Vermivora chrysoptera), which are considered an early successional forest specialists, we used spot‐mapping and radiotelemetry to record song perches and delineate song territories for breeding male golden‐winged warblers in northwestern Minnesota, USA. We also used radiotelemetry to record locations (song and nonsong perches) of a subsample (n = 12) of males throughout the day to delineate home ranges. We found that telemetry‐based estimates of song territories were 3 times larger and included more mature forest than those estimated from spot‐mapping. In addition, home ranges estimated using radiotelemetry included more mature forest than spot‐mapping‐ and telemetry‐based song territories, with 75% of afternoon perches located in mature forest. Our results suggest that mature forest comprises a larger component of golden‐winged warbler song territories and home ranges than is indicated based on spot‐mapping in Minnesota. Because it appears that standard observational methods can underestimate territory size and misidentify cover‐type associations for golden‐winged warblers, we caution that management and conservation plans may be misinformed, and that similar studies are needed for golden‐winged warblers across their range and for other songbird species. © 2012 The Wildlife Society.

ABSTRACT. Among shrubland-and young forest-nesting bird species in North America, Golden-winged Warblers (Vermivora chrysoptera) are one of the most rapidly declining partly because of limited nesting habitat. Creation and management of high quality vegetation communities used for nesting are needed to reduce declines. Thus, we examined whether common characteristics could be managed across much of the Golden-winged Warbler's breeding range to increase daily survival rate (DSR) of nests. We monitored 388 nests on 62 sites throughout Minnesota, Wisconsin, New York, North Carolina, Pennsylvania, Tennessee, and West Virginia. We evaluated competing DSR models in spatial-temporal (dominant vegetation type, population segment, state, and year), intraseasonal (nest stage and time-within-season), and vegetation model suites. The best-supported DSR models among the three model suites suggested potential associations between daily survival rate of nests and state, time-within-season, percent grass and Rubus cover within 1 m of the nest, and distance to later successional forest edge. Overall, grass cover (negative association with DSR above 50%) and Rubus cover (DSR lowest at about 30%) within 1 m of the nest and distance to later successional forest edge (negative association with DSR) may represent common management targets across our states for increasing Golden-winged Warbler DSR, particularly in the Appalachian Mountains population segment. Context-specific adjustments to management strategies, such as in wetlands or areas of overlap with Blue-winged Warblers (Vermivora cyanoptera), may be necessary to increase DSR for Golden-winged Warblers. Variables associées à la survie des nids de Paruline à ailes dorées (Vermivora chrysoptera) parmi les communautés végétales fréquemment utilisées pour nicherRÉSUMÉ. Parmi les espèces d'oiseaux d'Amérique du Nord qui nichent dans les milieux arbustifs et les jeunes forêts, la Paruline à ailes dorées (Vermivora chrysoptera) est l'une de celles dont les populations diminuent le plus rapidement en raison du peu de milieux de nidification. Afin de freiner cette baisse, la création et l'aménagement de communautés végétales de qualité sont nécessaires pour la nidification de l'espèce. Nous avons examiné s'il était possible d'aménager sur la base de caractéristiques communes dans une grande partie de l'aire de reproduction de cette paruline pour augmenter le taux de survie quotidien des nids (TSQ). Nous avons suivi 388 nids dans 62 stations réparties au Minnesota, au Wisconsin, dans l'État de New York, en Caroline du Nord, en Pennsylvanie, au Tennessee et en Virginie occidentale. Nous avons évalué trois séries de modèles de TSQ fondés sur les caractéristiques spatio-temporelles (type de végétation dominante, segment de la population, État et année), intrasaisonnières (stade du nid et moment durant la saison) et végétales. Parmi tous les modèles, les meilleurs montraient une association potentielle du taux de survie quotidien des nids avec l'État, le moment durant la saison, le pourcent...

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