MIGRATORY RESTLESSNESS IN CAGED BOBOLINKS (DOLICHONYX ORYZIVORUS, A TRANSEQUATORIAL MIGRANT)

Responses of Nesting Bobolinks (Dolichonyx oryzivorus) to Habitat Edges

-Avoidance of habitat edges may be contributing to reduced densities of grassland birds in small habitat patches. Nest densities for grassland-nesting Bobolinks (Dolichonyx oryzivorus) were much lower than expected within 25m of forest edges at three sites in New York, and that pattern ("edge avoidance") extended to 100m at one site. Nests located within 50 m of forest or wooded hedgerow edges ...

Natal and Breeding Dispersal of Bobolinks (Dolichonyx Oryzivorus) And Savannah Sparrows (Passerculus Sandwichensis) In An Agricultural Landscape

Visual pigment and oil droplet characteristics of the bobolink (Dolichonyx oryzivorus), a new world migratory bird

The retinal photoreceptors of a New World migratory bird, the bobolink (Dolichonyx oryzivorus) were examined using microspectrophotometry. Based on the absorbance spectra of their visual pigments and oil droplets, retinal photoreceptors include five classes of single cones, one double cone, and one rod. The single cones contain a long-wavelength pigment (lambda(max)=564nm) paired with a red or ...

Migratory Restlessness in an Equatorial Nonmigratory Bird

The urge of captive birds to migrate manifests itself in seasonally occurring restlessness, termed "Zugunruhe." Key insights into migration and an endogenous basis of behavior are based on Zugunruhe of migrants but have scarcely been tested in nonmigratory birds. We recorded Zugunruhe of African stonechats, small passerine birds that defend year-round territories and have diverged from northern...

Local parasite lineage sharing in temperate grassland birds provides clues about potential origins of Galapagos avian Plasmodium

Oceanic archipelagos are vulnerable to natural introduction of parasites via migratory birds. Our aim was to characterize the geographic origins of two Plasmodium parasite lineages detected in the Galapagos Islands and in North American breeding bobolinks (Dolichonyx oryzivorus) that regularly stop in Galapagos during migration to their South American overwintering sites. We used samples from a...