Kestrels Get a Hand with Housing
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Adapted from an article by Jim Crowell, Central Electric Ruralite Newsletter, October 1999 on the work of Don McCartney
INTRODUCTION
Legend says Johnny Appleseed journeyed across America planting apple seeds as he went as a means of improving the quality of life for humans and wildlife alike. Don McCartney’s scope of interest is a lot narrower, but in his own way, he’s getting the job done.
Don and his wife, Carol, are Central Electric members who live in the Bend (Oregon) area, and are trying to do their part in helping one or more bird species flourish in an area of dwindling habitat. To this end, Don, a retired certified public accountant from Portland, has been building and installing cedar nesting boxes in Central Electric’s territory in an effort to bolster the declining populations of the American Kestrel.
The American Kestrel or “sparrow hawk” is the smallest and most frequently seen member of the falcon family in North America. A prodigious predator for its size, it is especially proficient at keeping the population of field mice and other rodents in balance.
METHODS
To assist the kestrels in nesting and
producing young, Don and Central Electric have joined forces to place nesting
boxes on poles in areas where the rodent population has exploded in recent
times. Kestrels and bluebirds, however, have seen their natural nesting
sites—cavities of trees near open grassland—reduced due to the ever-increasing
encroachment of civilization.
In the past six months, Don has installed 10 boxes in snags and on old Central Electric poles in areas around Bend, Sisters, Cloverdale and Lower Bridge. “It’s not as easy to find good old snags (the kestrel’s normal nesting site) as it used to be, and so I’m very impressed with the way Central Electric has placed some of their older poles in strategic spots for me,” Don says. “The crews have been very helpful.”
Don also volunteers as part of a
national research project involving kestrels and the success of these new
nesting sites. At the end of the nesting
season, he files field data collected at his nests and submits it to the Cornell
Lab of Ornithology's Birdhouse Network in New York.
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Don removes three
American Kestrel fledglings from the nest of a bird box he built and installed
on a power pole supplied by Central Electric.
Assisting, from left, is Sisters naturalist Jim Anderson, Carol McCartney
and Sandi Van Aken of Lower Valley Turf Farms, owner of the property upon which
the pole was installed by a CEC crew. |
Don McCartney, left, and his wife, Carol,
assist Jim Anderson in banding 20 day-old kestrels.
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Assisting Don has been Jim Andersen,
scientist/naturalist and longtime resident of Central Oregon, who writes a
weekly column on nature for the Sisters Nugget newspaper.
Jim bands the birds to aid in the
study of their movements and migrations.
The kestrels are banded before they leave the box at an age of about 20
days old. In June and July, 20 nestlings
were banded in the boxes they put up.*
The effort is a modest beginning, compared to the major programs in at least 12 states and several Canadian provinces. In Iowa, 290 boxes—each one mounted on the back of an interstate freeway sign—dot every mile of I-35 from the Minnesota border to the Missouri border.
Now, the limiting factor is a lack of
sites in suitable habitat on private land.
Ideal habitat is open farm or ranchland, such as in the Cloverdale
area. Landowners who would like to be
considered for a free box on their property may contact Don
McCartney.
"In addition to the help we’ve had from Central Electric, we’ve also had great cooperation from the landowners who have sites that fit well with our programs,” Don says. “The Van Akens of Lower Valley Turf in Lower Bridge, and the Goosens in the Cloverdale area have been very cooperative.”
*In 2000, 43 kestrels
successfully fledged;
in 2001 67 kestrels successfully
fledged.
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Results from 2001 nesting season |
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1) On box size While the standard kestrel box has dimensions of 9 ¼” X 7 ¾” floor size (size recommended in Carrol Henderson’s Woodworking for Wildlife-Homes for Birds and Mammals, Pennsylvania Game Commission), I have found that a 7 ¼” X 7 ¾” box is quite adequate. Rather than 1” X 10” boards for all four walls, I use 1” X 8” boards for the front and back. This results in a box that is easier and safer to handle when mounting when 10’ to 12’ up a ladder. 2) On location Macrohabitat: I initially expected to have the best success locating boxes where kestrels are seen year-round in central Oregon, which are agricultural fields. The occupancy rate, primarily due to competition from European Starlings attracted to ubiquitous livestock, has been a dismal 15%. The most surprising discovery is that by far the highest occupancy rates (65-70%) have been in habitats where kestrels are seldom seen outside of nesting season. My home is in an open habitat of sagebrush, bitterbrush, and scattered juniper. A pair of kestrels consistently show up in April, lay eggs in early May, and the young fledge in July, after which time they’re “outta here,” not to be seen again until the following April. Yet in mid-winter, I can travel less than 10 miles to the farming/ranching areas, complete with (a few) kestrels and kestrel boxes that were unused the prior spring.
My observations reflect their conclusions, but with one major exception – the kestrels’ apparent affinity for both live junipers and juniper snags. The predominant tree species in our desert area is Western Juniper, in which kestrels very readily accept nest boxes. It was very much to my surprise that I found kestrels repeatedly using a box located 250’ deep in a juniper forest and that was originally intended for Northern Pygmy Owls. In sharp contrast, kestrels seem to strongly avoid boxes in Ponderosa pines. In all cases of these live trees, enough limbs were removed to provide for low concealment and a clear flight path to the box. |
Microhabitat: Tolan and Elder reported in “Influence of
nest box placement and density on abundance and productivity of American Kestrels
in central Missouri”, (Wilson Bulletin, 99(4), 1987): “Kestrels seemed to
prefer to nest in nest boxes even when there was an abundance of suitable
natural cavities nearby. Nest boxes that
were placed within 20 meters of wood lots, however, were used by fox squirrels,
Sciurus niger, which sometimes evicted kestrels. Wilmers (1983) reported that kestrels avoided
nest boxes near the borders of woods.
Kestrels rarely used boxes on live trees, using both poles and buildings
significantly more often”.
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