TOP 10 SPECIES LISTS
How have bird populations and communities changed over time? This question is central to the mission of the BBS, and we answer it by conducting detailed statistical analyses of the data that result in species population trend estimates. However, it is not always obvious what these trend estimates mean in terms of the bird communities we experience in our own backyards. So to provide insight into this question from a more general approach, we have listed below the ten most abundant species per state as detected on BBS routes in 1970 (except Alaska) and 1996. Though not a rigorous analysis of BBS data, we found it interesting to see how species have fared in relation to each other over the years and hope you do as well. To get a thumbnail sketch of how a particular species has managed between time periods, divide the total number of individuals by the sample size (N), number of routes surveyed, which will give you the average number of individuals detected per route each year. Though this measure is informative, you should defer to the BBS Results and Analysis home page (http://www.mbr.nbs.gov/bbs/bbs.html) for the estimated average rates of population change during the survey period.
All states have experienced some changes in top ten species composition
over the last 26 years, but for several species the changes have been dramatic.
For example, in 1970, House Sparrows ranked among the top ten species in
81% of the states and made the top four species in about half (52%) of
the states, but in 1996 they are listed among the top ten in only 21% of
the states. Similarly, Northern Bobwhite, which made the list in
17 (35%) states in 1970, are absent from the top ten in all but two states
(KS & OK) in 1996. On the other hand, American Crows and American
Robins have increased their standings in many states over the years.
American Crows ranked in the top ten in 43% of the states in 1970, but
by 1996, the number of states in which they ranked among the ten most abundant
species increased to 71%. American Robins follow a similar pattern,
going from the top ten in only 21% of the states in 1970 to the top ten
in 54% of the states in 1996. These are just a few obvious examples,
so take a look at the table below to see what other changes have occurred
in your state.
Since our last correspondence, there have been a couple of state BBS coordinator changes. In Maine, Linda Hornyak-Grieve has relinquished the role of state coordinator, and has been replaced by Judy Camuso (Maine Audubon society, P.O. Box 6009, Falmouth, ME 04105; 207/781-1330). Paul Schwalbe, the co-coordinator for Pennsylvania, has also decided to retire after 31 years of dedicated service to the BBS leaving Dan Brauning (RR 2, Box 484, Montgomery, PA 17752; 717/547-6938) as the sole coordinator for the state.
email: Bruce_Peterjohn@nbs.gov email: Keith_Pardieck@nbs.gov
tel: 301/497-5841 tel: 301/497-5843