I read Jim's, Ben's and others recent posts concerning American Kestrel populations with interest. Like Jim, I sometimes have days a field when I see very few kestrels. But then again, I also have days when they seem quite common, similar to Ben's view. My feeling concerning our regional kestrel populations is that they have definitely declined in some local areas, but have held their own in most other locations where their preferred habitat is abundant. I also think, for obvious reasons, that these declines are most noticeable in urban and suburban areas. The farther you get away from these rapidly developing areas and the further into the rural countryside you go, kestrels become much more common.
While American Kestrels are considered permanent residents in Ohio their movements throughout the state are complex and poorly understood. Some individual kestrels are certainly permanent residents but some breeding birds leave the state during the winter while other northern birds winter here. Other kestrels pass through Ohio as migrants during the spring and fall. So when discussing Ohio kestrel populations we have to consider permanent residents (Jan-Dec), summer breeders (April-July), winter residents (Oct-Feb) and migrants (March-May & Sep-Dec). All of this would suggest that kestrels are most numerous in Ohio from October through March, when migrants and winter residents augment the permanent resident population. It is also easier to see kestrels during this time of the year due to the lack of foliage.
The North American Breeding Bird Survey detected significant increases from 1966 to 1996 in the Till plains physiographic regions of the midwest and central U.S. (including Ohio). They go on to say that there was no significant change continent wide, but significant overall increases in the central region offset significant declines in New England and certain areas in the western region.
North American Birds cites the following factors as being responsible for local kestrel declines; reforestation, urbanization and residential development, modern clean farming practices, and lack of suitable nesting cavities. They suggest in some areas the use of insecticides may harm kestrels by significantly reducing summer prey.
As the compiler of the Cincinnati Christmas Bird Count for the past twenty years and a participant longer than that, I have noticed a significant kestrel decline on that count. Our count circle includes much of eastern Hamilton and western Clermont Counties (eastern Cincinnati and it's eastern suburbs). In the 1970's much of the eastern part of this circle was still fairly rural, but over the past 25 years urbanization and continuous development has all but eliminated kestrel (and Northern Bobwhite, Eastern Meadowlark, Northern Harrier etc.) habitat. In the 1970's the Cincinnati count averaged 106 kestrels per year (151 in 1975), 70 per year during the 1980's, and 34 per year during the 90's. Over the past five years we have averaged only 11 kestrels per year. That's a pretty significant decline. So yes, loss of habitat does reduce kestrel populations.
So as our large metropolitan areas increase in size and encroach into what was once rural countryside, kestrel habitats disappear and hence, so do kestrels. While Ohio's rural kestrel populations may have declined from previous heyday numbers, I believe they are still holding their own. It will be interesting to see the results of our OBBA II efforts.
Jay Stenger
Cincinnati, Ohio
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