Category: North America

Turdus migratorius (American robin) are more alert when solitary than in flocks

American Robin (Turdus migratorius) Science Article 5 abstract This study was undertaken to determine the relationship between foraging andalert behavior and group size in Turdus migratorius (American robin). We expected thatrobins would forage more than be alert in flocks and would be more alert than foragewhen solitary. Emily Sun, unknown Download article download full text […]

Observations on Remating in the American Robin, Turdus migratorius

American Robin (Turdus migratorius) Science Article 4 abstract In suburban Baltimore, from 1942 through 1950, I color-banded both members of15 pairs of Robins. At the end of 1951 the record of returns and rematings showedthe following: 1) Both members of eight pairs returned in the year following theirfirst known mating; there was one remating HERVEY […]

Photoperiod Experiments on the American Robin

American Robin (Turdus migratorius) Science Article 1 abstract The American Robin of southwestern British Columbia was tested in captivity under four light regimes: LD 8:16, 12:12, 16:8, all under artifical light, and natural daylight increment from LD 12:12 to 16:8. Robins under the latter two regimes gained in gonadal weight and in follicular and seminiferous […]

Behavioral Defenses Against Brood Parasitism in the American Robin (Turdus migratorius)

American Robin (Turdus migratorius) Science Article 3 abstract In response to avian brood parasitism, hosts may develop a number of defenses to reducethe negative consequences parasitism can have on the host’s reproductive success. Thesebehaviors may include aggression towards a parasite, rejection of parasitic eggs, or nestdesertion. Comparisons of populations that are exposed to parasitism and […]

Modeling Seasonal Interactions in the Population Dynamics of Migratory Birds

American Redstart (Setophaga ruticilla) Science Article 2 abstract UNDERSTANDING THE POPULATION DYNAMICS of migratory birds requires understanding the relevant biological events that occur during breeding, migratory, and overwintering periods. The few available population models for passerine birds focus on breeding-season events, disregard or oversimplify events during nonbreeding periods, and ignore interactions that occur between periods […]

Taxonomic relationships among the american redstarts

American Redstart (Setophaga ruticilla) Science Article 3 abstract In recent years certain bird taxonomists have indulged in what might be described as a veritable orgy of genus-lumping. Small genera, particularly monotypic genera, must, it seems, be somehow combined with one another, or shoehorned into larger genera (see, for example, the footnote on Uropsila, Paynter, 1960:430). […]

Prevalence of Hematozoa in Overwintering American Redstarts(Setophaga ruticilla): No Evidence for Local Transmission

American Redstart (Setophaga ruticilla) Science Article 4 abstract We examined American redstarts (Setophaga ruticilla) for protozoan blood parasites on their wintering grounds to determine whether transmission of these parasites occurs prior to spring migration. A total of 73 blood smears from 37 birds were examined for presence and intensity of infection. Thirty-six birds were sampled […]

Delayed plumage maturation and thepresumed prealternate molt in american redstarts

American Redstart (Setophaga ruticilla) Science Article 5 abstract The American Redstart (Setophaga ruticilla) is one of about 30 sexuallydichromatic North American passerine species in which males exhibit adelayed plumage maturation (Rohwer et al. 1980). Males in their first winterand in their first potential breeding season are largely like females incoloration. SIEVERT ROHWER, WILLIAM P. KLEIN, […]