Printer-friendly1999 Bowhunter Sighting Log Summary
Changes in Sighting Rates for Deer and Furbearers
The second year of the statewide Bowhunter Sighting Log revealed changes in sighting rates for deer and furbearers in large areas of New York. Localized changes occurred for turkey and for grouse in Suffolk and Westchester counties.
The Log began in 1995 in several pilot areas of New York. Three years later it was implemented statewide. This means that 1999 was the first year that changes in sighting rates could have been detected in most of the state. For pilot areas, 1999 was either the 4th or 5th year of operation. This longer time span provides more confidence in trends for the pilot areas.
The log makes use of the observations of thousands of bowhunters across the state. Participants are asked to record their hunting hours and wildlife observations throughout the archery season. The objective is to collect reliable information on sighting rates for a variety of species. Changes in sighting rates are thought to be related to wildlife population trends.
Upstate participants are asked to record observations for raccoon, coyote, deer, turkey, red fox, gray fox, and several species that are less common including bobcat, river otter, fisher, moose, and black bear. Downstate participants hunting in Suffolk and Westchester county record the six major species plus striped skunk, ruffed grouse and bobwhite.
How the log works: For deer, turkey, grouse, bobwhite, and most of the furbearers, we develop a "sighting rate" of the number of sightings for each species per thousand hours of field time. Each participant's sighting rates are compared with his or her rates from previous years. Then information from all participants is combined to determine the average change for each area. Summaries are compiled for wildlife management units and larger areas.
Attrition produced a modest decline in log participation in 1999. Over 4,000 bowhunters participated, a third less than in the previous year. These bowhunters logged 59,000 days and 236,000 hours. This level of dropouts is expected, but it does mean that more participants are needed in several parts of the state. Additional participants are critically needed in the areas shown to the right. A shortage of participants makes it less likely that we would detect changes in sighting rates in these areas.
Results: For most species and areas the 1999 sighting rates were not significantly changed from the previous year. In areas where changes did occur, the most common changes were increased rates for deer and decreased rates for red fox, gray fox and coyote. Sighting rates for turkeys also increased in many areas. The maps below indicate broad areas where sighting rates changed for deer and gray fox.
The bowlog pilot areas, which have been running since 1995, produced information on longer term trends. Trends for deer and coyotes from two of the pilot areas are shown in the graphs below. For the other species and pilot areas there was no significant upward or downward trend.
Annual differences in food supplies, weather patterns, prey distribution, and abundance contribute heavily to changes in sighting index for any species between individual years. This means that even a large difference in sighting rates from one year to the next may not mean that the population level has changed. However, trends observed over time periods such as those in the pilot areas provide stronger evidence for population change. As time goes on and as more participants are added in under-represented areas, we hope to have meaningful population trend information for the entire state.
A final important use of the Log is to monitor species with a limited distribution in New York, such as moose, black bear, and fisher upstate, and turkeys on Long Island. Typically little is known about occurrence of these species in the marginal parts of their range. By comparing information from bowhunters all across the state, we can learn more about distribution and status of these species throughout New York.
Bowhunter sighting log forms and instructions are available each year in September and October. Please ask your bowhunting friends from northern New York and other under-represented areas to sign up! (To sign up, call 518 402-8878, send a note or email to mailto:fwwildlf@gw.dec.state.ny.us?subject=bowlog, or contact your regional DEC office.) Increased participation will provide better information and will help us respond appropriately to public needs.
Thanks to all participants during the years the log has been implemented. Your continued participation is especially helpful. While new participants are always welcome, our statistical methods make the best use of information from those who continue for more than one year. Working together, we will increase our understanding of New York's wildlife.
A contribution of Federal Aid in Wildlife Restoration Grant NY:W-173-G