Microclimatic Factors of Blacktop Roads as they Affect Bird Behavior, Diurnal Distribution and Range

[摘要] Between 11 May and 30 September 1974, 2127 birds were observedon the surface of blacktop roads. Relationships between the presenceof birds on the road and air temperatures were evaluated against datafrom four microclimates: the road in the sun, the road in the shade,the litter layer under pines, and the ground layer in herbaceous vegetation.The presence of birds also was evaluated relative to varyingcloud cover, wind velocity, precipitation, and dampness of the roadsurface. At the times when the maximum number of birds was presenton the road surface, the temperature of the macadam road in the sunwas significantly warmer than the ambient air temperature or themicroclimates of the litter layer beneath the pines or the herbaceousground layer.It appeared that the birds used the macadam roads for warmth.The existence of the man-made microclimate of the macadam road appearedto influence bird behavior, diurnal distribution, and possiblythe northward distribution of some species.

[发布机构] University of Wisconsin-Stevens Point, College of Natural Resources