Anthropogenic changes in climate and land use are driving changes in migration patterns of birds worldwide. Spatial changes in migration have been related to long-term temperature trends, but the intrinsic mechanisms by which migratory species adapt to environmental change remain largely unexplored. We show that, for a long-lived social species, older birds with more experience are critical for innovating new migration behaviours. Groups containing older, more experienced individuals establish new overwintering sites closer to the breeding grounds, leading to a rapid population-level shift in migration patterns. Furthermore, these new overwintering sites are in areas where changes in climate have increased temperatures and where food availability from agriculture is high, creating favourable conditions for overwintering. Our results reveal that the age structure of populations is critical for the behavioural mechanisms that allow species to adapt to global change, particularly for long-lived animals, where changes in behaviour can occur faster than evolution.

Aim Animal movement is an important determinant of individual survival, population dynamics and ecosystem structure and function. Nonetheless, it is still unclear how local movements are related to resource availability and the spatial arrangement of resources. Using resident bird species and migratory bird species outside the migratory period, we examined how the distribution of resources affects the movement patterns of both large terrestrial birds (e.g., raptors, bustards and hornbills) and waterbirds (e.g., cranes, storks, ducks, geese and flamingos). Location Global. Time period 2003–2015. Major taxa studied Birds. Methods We compiled GPS tracking data for 386 individuals across 36 bird species. We calculated the straight‐line distance between GPS locations of each individual at the 1‐hr and 10‐day time‐scales. For each individual and time‐scale, we calculated the median and 0.95 quantile of displacement. We used linear mixed‐effects models to examine the effect of the spatial arrangement of resources, measured as enhanced vegetation index homogeneity, on avian movements, while accounting for mean resource availability, body mass, diet, flight type, migratory status and taxonomy and spatial autocorrelation. Results We found a significant effect of resource spatial arrangement at the 1‐hr and 10‐day time‐scales. On average, individual movements were seven times longer in environments with homogeneously distributed resources compared with areas of low resource homogeneity. Contrary to previous work, we found no significant effect of resource availability, diet, flight type, migratory status or body mass on the non‐migratory movements of birds. Main conclusions We suggest that longer movements in homogeneous environments might reflect the need for different habitat types associated with foraging and reproduction. This highlights the importance of landscape complementarity, where habitat patches within a landscape include a range of different, yet complementary resources. As habitat homogenization increases, it might force birds to travel increasingly longer distances to meet their diverse needs.

This paper presents CraneTracker, a novel sensor platform for monitoring migratory birds. The platform is designed to monitor Whooping Cranes, an endangered species that conducts an annual migration of 4, 000 km between southern Texas and north-central Canada. CraneTracker includes a rich set of sensors, a multi-modal radio, and power control circuitry for sustainable, continental-scale information delivery during migration. The need for large-scale connectivity motivates the use of cellular technology in low-cost sensor platforms augmented by a low-power transceiver for ad-hoc connectivity. This platform leads to a new class of cellular sensor networks (CSNs) for time-critical and mobile sensing applications. The CraneTracker is evaluated via field tests on Wild Turkeys, Siberian Cranes, and an on-going alpha deployment with wild Sandhill Cranes. Experimental evaluations demonstrate the potential of energy-harvesting CSNs for wildlife monitoring in large geographical areas, and reveal important insights into the movements and behaviors of migratory animals. In addition to benefiting ecological research, the developed platform is expected to extend the application domain of sensor networks and enable future research applications.

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ABSTRACT. Once nearly extirpated, the Eastern Population (EP) of Greater Sandhill Cranes (Grus canadensis tabida) has increased in number and expanded its range in breeding and wintering areas. Data from Christmas Bird Counts (CBCs) and Breeding Bird Surveys (BBSs) were used to delineate changes in the wintering and breeding area distributions during the period from 1966 to 2013. Crane densities were plotted to the centroid of CBC circles or BBS routes, and the Geographic Mean Centers (GMCs) for wintering and breeding populations were calculated. RESUMEN. Cambios en el numero y la distribución de Grus canadensis tabida en la población del orienteUna vez casi extirpada, la población de Grus canadensis tabida del oriente, ha incrementado en numero y expandido su rango enárea de reproducción e invernales. Datos de Conteos Navideños (CN) y Censos de Aves Reproductivas (CAR) fueron utilizados para delinear cambios en la distribución en elárea de invernal y reproductiva durante el periodo desde 1996 hasta 2013. Las densidades de las Grulla fueron graficada al centroide de los círculos de CN y las rutas CAR y fueron calculados los Centros Geográficos Promedio (CGP) para las poblaciones invernales y reproductivas. El numero de G. c. tabida detectados durante la temporada reproductiva ha incrementado sostenidamente desde 1996, con solo seis aves observadas en 1996 y 1046 observadas en el 2013. Los CGP de las poblaciones de G. c. tabida han permanecido en Wisconsin durante el plazo de 47 años. Los números totales de G. c. tabida obtenidos al oriente de los Estados Unidos durante los CN creció desde 423 en 1965 a 46,194 en 2012, con un numero pico de 55,826 en 2011. tabida fue localizado en la Florida durante los periodos 1996 a 1997 y 1978 a 1989, pero se desplazo al nororiente por casi 4°de latitud (hacia Georgia) entre 1990 -2001 . Entre 2002, el CGP de ha desplazado un grado más al norte al igual que casi un grado de longitud al occidente. Las poblaciones orientales de G. c. tabida pueden continuar invernando más al norte y permanecen en las zonas más septentrionales más tarde en el otoño antes de migrar hacia el sur. Factores como el clima anual, el cambio climático a largo plazo, y los cambios en el uso del suelo pueden influir en todas las tendencias demográficas futuras, y cambios tanto en la cría como rangos invernales de la población oriental de G. c. tabida.

This paper presents CraneTracker, a novel sensor platform for monitoring migratory birds. The platform is designed to monitor Whooping Cranes, an endangered species that conducts an annual migration of 4, 000 km between southern Texas and north-central Canada. CraneTracker includes a rich set of sensors, a multi-modal radio, and power control circuitry for sustainable, continental-scale information delivery during migration. The need for large-scale connectivity motivates the use of cellular technology in low-cost sensor platforms augmented by a low-power transceiver for ad-hoc connectivity. This platform leads to a new class of cellular sensor networks (CSNs) for time-critical and mobile sensing applications. The CraneTracker is evaluated via field tests on Wild Turkeys, Siberian Cranes, and an on-going alpha deployment with wild Sandhill Cranes. Experimental evaluations demonstrate the potential of energy-harvesting CSNs for wildlife monitoring in large geographical areas, and reveal important insights into the movements and behaviors of migratory animals. In addition to benefiting ecological research, the developed platform is expected to extend the application domain of sensor networks and enable future research applications.

Recent detections of large gatherings of Whooping Cranes suggest that flock sizes may be increasing at some stopover locations during both the spring and fall migrations. We used the public sightings database managed by the US Fish and Wildlife Service from 1942 to 2018 to analyze data for long-term trends in group size. We then examined the spatial distribution of large groups to explore potential explanations for these occurrences. The proportion of Whooping Crane groups comprised of 2, 3, and 4-6 individuals showed no trend over time. However, observations of individuals showed a declining trend and groups of 7-9 and !10 showed an increasing trend. The frequency of groups observed exceeding 5 and 10 individuals were better predicted by survey year than by Whooping Crane population size suggesting that an increasing population is not the sole driver of large group occurrences. Our results indicate that large groups occur disproportionately within the 50% migration corridor, at staging areas within the first or last 20-30% of the migration path, and near conservation-managed wetlands, particularly within the southern Great Plains. Our results suggest that in addition to population growth, conspecific attraction, location within the migration corridor, and habitat loss may be contributing to large group occurrences. Further research is needed to determine the degree to which these factors influence large Whooping Crane group formation. The gathering of large numbers of Whooping Cranes in a single location presents potential tradeoffs for the species. While increasing group sizes may improve threat detection and avoidance, it comes at a cost of increased disease and mass mortality risk.

A successful species reintroduction depends, in part, on the correct identification of suitable habitats. In cases where a species has been extirpated from a region for decades, however, this task is fraught with uncertainty. Uncertainty can be minimized and adjusted for by monitoring and adaptive management. The central goal of this study was to identify reintroduction sites that facilitate dispersion of whooping cranes (Grus americana), a federally listed endangered species, into optimal habitat as quickly as possible. First, we described the habitat selection of breeding home ranges for reintroduced whooping cranes in and around Necedah National Wildlife Refuge of central Wisconsin. We defined home ranges as 95% fixed spatial kernel density estimates from location data gathered from nesting whooping cranes from April through July 2005–2010. Whooping crane home ranges contained more emergent herbaceous wetlands than expected by chance and less developed or barren land, forest, and scrubland. Breeding whooping crane home ranges usually were composed of distinct nesting territories and off‐territory elements; when moving off‐territory, cranes decreased wetland selection and increased selection for open uplands. Second, we used habitat composition values and strength of selection (as determined by Jacob's index) to create a habitat suitability map to identify potential habitats that breeding whooping cranes could use in unoccupied eastern Wisconsin. With this method, we identified 2 large suitable wetland complexes within our study area associated with the Fox and Rock Rivers. Based on this analysis, the Whooping Crane Eastern Partnership began releasing whooping cranes into White River Marsh State Wildlife Area and Horicon National Wildlife Refuge in 2011. © 2014 The Wildlife Society.