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Seasonal Differences in Rufous Hummingbird Nest Height and Their Relation to Nest Climate
Author(s) -
Horvath Otto
Publication year - 1964
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.2307/1933836
Subject(s) - microclimate , nest (protein structural motif) , deciduous , ecology , hummingbird , nest box , spring (device) , geography , environmental science , biology , seasonal breeder , mechanical engineering , biochemistry , engineering
Nest height for rufous hummingbirds differs significantly between spring and summer nests in southern British Columbia. Though spring and summer microclimates are different, the microclimate of nest sites is similar in the spring nest sites and summer nest site. Hummingbirds build their nests at low levels in conifers in spring, but higher and in deciduous trees in the summer. The effect of the stand in reducing the ambient temperature is greater at this low nest site in conifers than at the higher sites in deciduous trees. The low nest sites are more protected from climatic extremes than the high nest sites, and thus the seasonal effects of the microclimate are moderated. Radiation is higher in summer than in spring, which results in extreme climatic amplitudes near the ground; this makes the low nest sites less favorable for the birds in summer. The summer nest sites are located mainly in the crown of deciduous trees and experience the temperature reducing effect of the intensive evapo—transpiration of these trees. This means an effective protection against heat, which would not be provided at the level of spring nest sites.