Species with different reproductive schedules may differ in how they respond to the annual change in photoperiod (the adaptive specialization hypothesis). Seasonally breeding species are predicted to use photorefractoriness to terminate reproduction prior to inclement conditions in autumn and winter, whereas opportunistically breeding species may not exhibit photorefractoriness. We tested for a...

~UMMARY: The feeding ecology of the starling, Sturn us vulgaris, was studied in Canterbury from 1968-71. StarHngs fed in f10cks which varied seasonally in composition and behaviour. During breeding, parent birds fed in smaIl isolated multi specific flocks which after breeding, coalesced into much larger more regimented monospecific flocks. Starlings dietary patterns varied seasonally both in di...

Among the many explanations for the large biological diversity of Mexico is that it is the result of the contact between the Nearctic and Neotropical biotas; however, this contact-related explanation is not fully satisfactory and needs further examination in the light of historical biogeography. We offer newer insights into this issue by examining the history of the flora and the vegetation het...