Figure 2: Map showing where Evening Grosbeak numbers are exhibiting the most serious declines between 1980 and 1998.
Figure1: Animated map of Evening Grosbeak distribution between 1988 and 1998.
Patuxent Wildlife Research Center
This species' Breeding Bird Survey trend map available at the Patuxent Wildlife Research Center's website documents a patchwork quilt across North America, with nesting kestrels increasing some regions and decreasing in others.
The fluctuation in numbers of kestrels on Christmas Bird Counts in the 1990's, detailed in the second map, perhaps shows how this small falcon fares after harsh winters, or at least how far the migratory birds have moved by early winter. In addition, the conversion of much agricultural land to urban areas could adversely affect American Kestrels; nesting cavities, fields and thickets, and the American Kestrel's prey base itself may be in decline over many areas of North America. To view animation, click on map.
The decade-interval map illustrates low numbers of American Kestrels on CBC's in 1958, with a steady increase in numbers found per party-hour until 1988, then a notable drop to 1997. The low numbers in the '50's, increasing until the '90's, may well represent a comeback in numbers of kestrels following the banning of the use of the pesticide DDT in the 1960's. To view animation, click on map image.