as we keep warm under down comforters in winter, many birds
improve nest insulation during incubation by adding feathers
and down to their nests. The advantage of insulation must be
weighed, however, against possible added conspicuousness of
the nest to predators and brood parasites and the danger of
overheating the nestlings. Zoologist Anders Moller surveyed
European passerine nests to determine which birds feathered
their nests and how much feather lining they added. Moller
found that feathers are more likely to be incorporated into
nests of birds that breed early in the year, particularly if
they are small and have a more northerly distribution and
especially if they are cavity nesters. The latter, of
course, need not worry about feathers increasing the
conspicuousness of their nests.
The source of feathers for nests is often the brood patch (a ventral area plucked bare to facilitate heat flow from the adult to the eggs). Grebes, waterfowl, shorebirds, gallinaceous birds, passerines, and birds of prey are among those that pluck brood patches. Interestingly, some birds incorporate feathers from other species into their nests. Molted feathers of ptarmigan are routinely used by redpolls, Snow Buntings, and some longspurs. You might try making available a handful of down from an old pillow to northern backyard breeders in early spring and see whether it is taken.
SEE: Masterbuilders; Nest Lining; Nest Materials; Eggs and Their Evolution; Incubation: Heating Eggs; Brood Patches.
Copyright ® 1988 by Paul R. Ehrlich, David S. Dobkin, and Darryl Wheye.