Hi Tweets,

I am assuming that the discussion is about Common Nighthawk (CONI) decline in western WA? Here in Yakima County CONI are still fairly common. I hear and see them nightly over my house east of Yakima and I also see them quite readily and almost daily while out working in the ponderosa pine zone west of Yakima in the Wenas Valley, Ahtanum and Mud Lake areas. In late summer, CONI seem to congregate in quite large flocks over orchards in the evening and along the Yakima River, maybe concentrating foraging in areas of high insect abundance in preparation for migration. I have lived here for 9 years and they are always a common sight here. If lack of insects were the problem, I would expect that they would be impacted more here due to the amount of agriculture spraying for insects that occurs over such a large geographic area. It is hard to imagine that flying insects would be so much less abundant west of the Cascades to account for such regional disparity in population size.

Habitat quality as well as potentially higher predation rates may offer more reliable explanations than insect abundance. The dry slopes of the East Cascades offer a more open understory with areas of wide open grassy zones mixed with talus that offer the type of nesting habitat this species prefers. This is particularly true from the ponderosa pine zone to the shrub-steppe. Although we do not have the large gull and crow populations here (away from cities proper) to prey on CONI eggs, we have our fair share of ground predators such as skunks, coyotes, California ground squirrels, badgers, etc., which are quite effective at preying on eggs and young of ground nesting birds.

Unfortunately, determining reasons for a species decline in a given region is fairly difficult and the hypothesis offered by many individuals are intriguing and some perhaps, worthy of study. However, trying to determine the reason for a decline after it has occurred is ripe with difficulties.

Jeff Kozma
Yakima
jeff k at charter dot net