Survey helps keep tabs on bird populations

By Thelma Dalmas
Published: June 10, 2008

Earlier this month, John and I finished running our Covesville Breeding Bird Survey for the 35th consecutive year. The survey can provide data that acts as a barometer of the viability of individual species.

These surveys, sponsored by the Patuxent Wildlife Research Center, take place in both the United States and Canada every summer. Approximately 4100 breeding surveys were done last year, more than 40 of which were completed in Virginia.

Since the data from across North America will be compared, it is important that a strict protocol is followed. We begin our survey at 5:22 a.m. when we make our first stop on the designated route. I get out of the car, listen for three minutes and write down both the species and number of every bird that I hear. We drive the car one-half mile down the road, repeat the procedure and continue for 50 stops. Later in the day, when I have enough light to see, I can also count any bird that I observe.

The information gathered from years of such surveys is invaluable for studying population trends. In fact, without some kind of hard numbers, we can do little more than note that some birds do not seem as abundant as they had been in past years. For instance, many of us may have noticed that bobwhites seem to be less common than they were 25 years ago.

In looking back over the data from my Covesville Survey, I noted that over a 40-year period bobwhite numbers have decreased alarmingly. From a high count of 66 birds in 1968, the decline has been steady: 25 in 1978; 14 in 1988; 3 in 1998; and this year we found only one bird. Unfortunately, this trend is reflected across most of the bird’s range, and has attracted the attention of both federal and state wildlife managers. Habitat restoration programs are now underway in a number of areas, and we hope that the situation can be remedied.

Even more discouraging, some species have completely disappeared from the Covesville route. Although never common, we once found loggerhead shrikes, grasshopper sparrows and kestrels breeding in the area. We have not seen any of these birds for the past 10 years.

Of course, not all of the news is bad. Some birds, such as the red-eyed vireo, eastern bluebird and cliff swallow, seem to be either holding steady or actually increasing in number. The important aspect of this type of survey is to monitor the population and be alert for changes. If a species appears to be in trouble, then we can look for solutions while there is still time. None of us wants to be in that situation described by the old song, “I didn’t know what I had until it was gone.”

News and Notes
For those who would like more information about attracting purple martins to their yards, the 14th Annual Purple Martin Field Day is set for Saturday, June 21. It is scheduled for 9:30 a.m. to noon at the farm of Merle and Lance Wood in Louisa County. You can learn how to establish a colony of purple martins, including information on housing requirements and protection devices. There will also be a short nesting box trail tour, featuring nest boxes for different species of birds. Please bring a lawn chair. For more information, contact Ron Kingston at .