Category: Icteridae

Natural and induced magnetization in the bobolink, dolichonyx oryzivorus (aves: icteridae)

Bobolink (Dolichonyx oryzivorus) Science Article 1 abstract The magnetic characteristics of the heads from 28 bobolinks [Icteridae:Dolichonyx oryzivorus (L.)] were analysed using remanence magnetometers. Thenatural remanent magnetization of 12 freshly preserved heads averaged 3-20xl0~7electromagnetic units (e.m.u.) (le.m.u. = 103Am~’) and was oriented horizontallyfrom side to side. An electromagnet was used to induce magnetization with externalfield […]

Male and Female Reproductive Strategies in the Polygynous Bobolink

Bobolink (Dolichonyx oryzivorus) Science Article 6 abstract Most species of birds are socially monogamous, however approximately 8% of bird species are polygynous. By mating polygynously,females lose paternal care, but might gain access to a superior territory or male. We examined five factors that affect polygyny inbobolinks: territory size, perching sites, predation rate, insect abundance, and […]

Multiple paternity in a territorial passerine: the bobolink

Bobolink (Dolichonyx oryzivorus) Science Article 8 abstract Electrophoretic and behavioral evidence corroborate the conclusion that Bobolink (Dolichonyx oryzivorus) females occasionally copulate with more than one male, whichresults in the insemination of a single clutch of eggs by those males. In 2 of 12 families from which blood samples were obtained from the mother, the putative […]

Factors affecting how male and female bobolinks apportion parental investments

Bobolink (Dolichonyx oryzivorus) Science Article 7 abstract Male and female Bobolinks (Dolichonyx oryzivorus) adjust the amount of time spent brooding and provisioning nestlings at primary nests in light of prevailing weather conditions and food availability. Males brood nestlings less and feed them more (mg/h) when food is scarce, regardless of weather conditions. Primary (i.e., first-mated) […]