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We studied House Finch Carpodacus mexicanus roosting behaviour during the non-breeding season using radiotracking and direct observations in Ithaca, NY, USA. In contrast to what has been reported in the literature and in contrast to what should be expected from Newton's European studies of cardueline finches, House Finches roost in small groups (mean 3.5; maximum 11) and do not display at roost sites. Seventy-seven per cent of the birds re-used the same tree on successive observations. In winter, birds re-used the same roost tree more often than in the autumn, and birds with mycoplasmal conjunctivitis tended to move more between roost trees than did birds without conjunctivitis. A small number of radiotagged birds that roosted in the same tree were observed together in the daytime more often than by chance, suggesting the existence of social bonds between birds (some same sex) during the non-breeding season. In the autumn the birds often roosted in leafed deciduous trees and closer to their daytime feeding locations than they did in winter. In winter all birds roosted in evergreen trees. It is possible that the reliable and predictable food sources at feeding sites offered by the public might have changed House Finch roosting behaviour. [ABSTRACT FROM AUTHOR]

In early 1994, a novel strain of Mycoplasma gallisepticum (MG)--a poultry pathogen with a world-wide distribution--emerged in wild house finches and within 3 years had reached epidemic proportions across their eastern North American range. The ensuing epizootic resulted in a rapid decline of the host population coupled with considerable seasonal fluctuations in prevalence. To understand the dynamics of this disease system, a multi-disciplinary team composed of biologists, veterinarians, microbiologists and mathematical modelers set forth to determine factors driving and influenced by this host-pathogen system. On a broad geographic scale, volunteer observers ("citizen scientists") collected and reported data used for calculating both host abundance and disease prevalence. The scale at which this monitoring initiative was conducted is unprecedented and it has been an invaluable source of data for researchers at the Cornell Laboratory of Ornithology to track the spread and magnitude of disease both spatially and temporally. At a finer scale, localized and intensive field studies provided data used to quantify the effects of disease on host demographic parameters via capture-mark-recapture modeling, effects of host behavior on disease and vice-versa, and the biological and genetic profiles of birds with known phenotypic characteristics. To balance the field-based component of the study, experiments were conducted with finches held in captivity to describe and quantify the effects of experimental infections on hosts in both individual and social settings. The confluence of these various elements of the investigation provided the foundation for construction of a general compartmentalized epidemiological model of the dynamics of the house finch-MG system. This paper serves several purposes including (i) a basic review of the pathogen, host, and epidemic cycle; (ii) an explanation of our research strategy; (iii) a basic review of results from the diverse multi-disciplinary approaches employed; and (iv) pertinent questions relevant to this and other wildlife disease studies that require further investigation.