White-winged doves are increasing both in numbers and occupied areas. Photo by Bob Walker
By ROBERT DRYJA
Los Alamos
Citizen science refers to individuals collecting and submitting data to an organization that then collates the data from many people. The Ornithology Department of Cornell University has been collecting bird sightings for thirty years for the United States and Canada. The program is called “Project FeederWatch”. Participants provide weekly counts of the different species of birds that they see at their bird feeders during the winter months. The results provide a sense of what is happening to bird species throughout the North American continent or for individual states.
Project FeederWatch is accessible at https://feederwatch.org. A person can provide bird counts until next April.
Charts A and B provide examples of what is happening with White-winged doves in New Mexico. Approximately 30 percent of the sites reported these White-winged doves thirty years ago. This has increased to approximately 60 percent of the sites for the most recent eight years, (see Chart A). The number of doves seen at a site has increased as well. About 1 to 3 doves were seen at a site in the early years. This has increased to about 5 to 6 doves in the most recent 8 years, (see Chart B). White-winged doves are being seen at more sites as well as in larger numbers at the sites.
Information like this helps evaluate the impact of longer term global climate change or shorter term droughts. What is the tangible impact of a 1 degree increase in ocean temperature over 120 years? What happens when rain and snow decrease below average by 1 inch for 10 years? Do the changes in global ocean temperature and regional droughts reinforce or offset one another? These rather distant and abstract ideas become tangible when looking at birds at a bird feeder, year by year. White-winged doves would appear to be benefiting, whatever the ways global climate change and droughts are affecting New Mexico.
The white-winged dove species are increasing, but this does not mean all bird species are doing the same. The house finch is a counter-example. Chart C shows that house finches are seen at the great majority sites.
There has been only a small decrease from about 96 percent in 1999 to about 92 percent in 2017 for the sites. However a more distinct decrease occurs when the average number of house finches seen at a site is considered. Table D shows that the average group for house finches seen at a site reached a peak of an average of 16 birds in 1992. It has since declined to an average of about 6 to 7 birds for the past 6 years.
House finches are still wide spread but their numbers in an area are declining significantly. Climate change, drought or other factors are having an adverse impact.
Bird watching is interesting because of the variety of birds that may be seen. Their behavior from year to year creates surprises. A flock of fifty red-winged black birds may appear one day after not being present for several years. The significance of climate change or draught may become apparent in the distribution or number of birds present from year. How many species are increasing like white-winged doves and how many species are declining like house finches? What is happening for the rest of the North American continent?
House finches are seen in many areas but their numbers in occupied areas are decreasing. Photo by Bob Walker
