Usually, the predators that have the greatest impact on ground-nesting birds (like all of our upland species) are nest predators. Raccoons often top the list. One reason is that as fur prices have dropped and trapping pressure has declined (and the animal rights crowd has done their best to make it politically incorrect to wear fur), numbers of furbearers have increased. Another negative impact on trapping has resulted from the decreasing number of farmers. A lot of farm kids used to make their spending money by running a trap line. Not nearly as many farm kids these days, not as popular to run a trap line, and easier money to go into town and work in a fast food restaurant. The Iowa DNR used to sell something over 5,000 youth trapping licenses annually. These days it's more like 500.
Definitely more concern about West Nile Virus these days. Even in years with good drumming counts when improved grouse numbers are anticipated, the expected population bump doesn't seem to happen. Although studies have shown that quite a few adult grouse shot by hunters have been exposed to WNV (contain antibodies) but have survived, science seems to indicate that it's more lethal on chicks. If that's accurate, that would explain why--even when drumming counts are high and nesting conditions are good--grouse numbers don't show much of an increase, if any.
Last edited by L. Brown; 02/23/20 07:25 AM.
