Fecal corticoid monitoring in whooping cranes (Grus americana) undergoing reintroduction
Abstract 10.1002/zoo.20033.abs We used radioimmunoassay to determine fecal corticoid concentrations and assess potential stress in 10 endangered whooping cranes (Grus americana) undergoing reintroduction to the wild. Fecal samples were collected shortly after hatching at a captive facility in Maryland, during field training in Wisconsin, and throughout a human-led migration to Florida. After a 14-day decline […]
Differential assessment of environmental information in a migratory and a nonmigratory passerine
Migratory birds stay in a particular area for only short periods and must rapidly acquire appropriate information about stopover sites. In contrast, resident birds can update their knowledge whenever necessary. In a novel environment migrants are thus predicted to assess relevant information faster than nonmigrants. We tested this prediction with two closely related species, the […]
Female polar bears, Ursus maritimus, on the Barents Sea drift ice: walking the treadmill
For animals in dynamic habitats, the contribution of passive (i.e. by wind or current) and active (movements by the animals themselves) displacement determines whether their space use reflects physical or adaptive behavioural processes. Polar bears in the Barents Sea undertake extensive annual migrations in a habitat that is highly dynamic because of continuous sea ice […]
Relationships between locomotor behavior, morphometric characters and thyroid hormone levels give evidence of stage-dependent mechanisms in European eel upstream migration
In order to decipher movements during freshwater eel colonization, we experimentally characterized individual locomotor behavior of two eel life history stages: elvers and yellow eels. A ramp located at the flume tank upstream side required a specific locomotor behavior to be ascended. Placing individually tagged eels in the middle of the tank three times successively […]
Plasma corticosterone increases during migratory restlessness in the captive white-crowned sparrow Zonotrichia leucophrys gambelli
Plasma corticosterone increases during the period of spring migration in a variety of bird species. Long-distance migrants show elevations in corticosterone specifically in association with the stage of flight, suggesting that corticosterone may support flight-related processes, for example, locomotor activity and/or energy mobilization. The pattern of corticosterone secretion as it relates to migratory flight has […]
Of Iguanas and Dinosaurs- Social Behavior and Communication in Neonate Reptiles
Newborn and newly hatched reptiles show diverse types of social behavior. Aggregation behavior in snakes, dominance in turtles, vocalization in crocodilians, and synchronized nest emergence, migration, and foraging behavior in iguanas are documented. Such evidence casts doubt on inferences about a generalized reptilian level of social organization qualitatively inferior to that found in birds and […]
Experimental and observational studies of seasonal interactions between overlapping life history stages in a migratory bird
Prior to reproduction, migratory animals are at the juxtaposition of three life history stages in which they must finish the non-breeding stage, initiate and complete migration, and prepare for the onset of breeding. However, how these stages interact with one another is not fully understood. We provide evidence that, for migratory birds that begin breeding […]