Saturday, July 04, 2009

Another Null Survey

Last year I made a multiple year commitment to survey for NightJars one night a year. NightJars are a family of crepuscular/nocturnal birds which in our area consist of the Common Nighthawk (not really a hawk!) and the Common Poorwill. Neither are really that common! Last year resulted in a good time, but a Null Survey. This year unfortunately produced similar results. It was however a great weekend regardless.
The survey is part of a nationwide effort led by the US NightJar Survey Network, part of the center for Conservation Biology of the College of William and Mary. They have mapped routes across the country and have asked volunteers to sign up for surveying a route, preferably for multiple years. It is believed that Nightjars are in a dramatic decline. This multiple year survey is intended to provide a basis for determining their population.
The surveys have to occur within a certain time frame (2 weeks in Idaho), on a clear night, with the moon visible. I chose early in the two week schedule as the moon rises later each day. Early in the cycle the survey can begin at 10pm. Late in the cycle it cannot begin until 2am!
We recently heard reports of a Great Gray Owl family in the area. Karyn and I headed up soon after my classes were out for the week to get a good campsite and to search for the Great Gray Owl. We did not find the family, but we did find one of the adults!
Great Gray Owl adult.
This adult was calling by vocalizing a single low call note. The call was answered by another Great Gray which was further back in the trees, probably 100-200 feet. We didn't see the others, as we didn't want to stick around too long and potentially disturb a new family. It is somewhat rare for them to be nesting in the area. I hope they are successful in raising their young and return to nest in future years.
While the day was beautiful the clouds poured in that evening. We would have to delay the nightjar survey for at least a day. We did go out wildlife watching where this Bald Eagle made its appearance.
Bald Eagle (Karyn's photo).
Friday morning we hiked down the Marsh Creek trail. Lots of birds - Western Tanagers, Ruby-crowned Kinglets, Yellow-rumped Warblers, Yellow Warblers, Hairy Woodpecker, Mountain Chickadees, Chipping Sparrows, Warbling Vireos, Swainson's Thrushes, etc. We saw one hummingbird which might have been a Rufous, but as they often do, it wouldn't hold still. For the non-avian fans, there were lots of Pikas, relatives to rabbits. We passed 5 scree fields, each supporting at least one or two.
Pika collecting grass.
That afternoon, the clouds rolled in. We might have to cancel our survey again! If not tonight, then next weekend at 2am! nasty! We ran into some friends who were also camping. They invited us to dinner. Excellent dutch oven prime rib. About 9pm, the sky began to clear. Woo hoo! We decided to go start preparing to conduct the survey. At 9:30pm it looked better still, we were on! We drove to start the survey.
We started the survey at 10:02pm. The survey consists of a 6 minute listening period performed at each of ten sites, each separated by one mile. Since we had surveyed this route last year, all of the points were established and loaded into my GPS unit. Thus, the whole survey would take just under 2 hours. In each six minute period, we note how many of each species of Nightjar that is heard. Simple enough. Except, there were no Nightjars to be heard. Bummer. However, it was a beautiful night with no wind and a nearly full moon. Numerous Wilson's Snipes were winnowing in the distance. This is a sound that their tail feathers make as they perform aerial flight displays. Six or seven of the points had snipes that could be heard in the distance. We heard one coyote howl.
The null survey is still a very valuable result, equal at least in value to a survey where birds are found. A single survey with no birds doesn't mean that there aren't any there. Two surveys with no birds still doesn't prove their absence, but it does decrease the chance. This particular area is prime habitat for NightJars. Why aren't they there?
Today before we headed home we had a great Mountain Tandem ride on the Fisher Creek Trail. The trail we were married on 15 years ago, on a mountain tandem! Videos from that will be posted later.
On the way out of Stanley we spied a Sandhill Crane chick!
Sandhill Crane family (Karyn's photo).
This is the first chick we have seen this year. It was running back and forth between the parents whenever they would grab some food. In all, it was a great weekend.


Unknown said...

Bad luck about no nightjars.
But at least you saw something..

John B. said...

Too bad you got another null result. Do you think that none or present or that they just didn't call during your survey?

wolf21m said...

After last year I was thinking it was too early or they just weren't active. Last year's survey was two weeks earlier. After the null result this year, I am not so sure. I have seen Common NightHawks in the general area (within 20 miles), but never on this particular route. I don't know what the statistical models use for their assumptions (x% chance occupied after one null survey, Y% after two null surveys,...). I'd like to have a closer look at their models.

Heidi said...

sweet about the great gray! and awesome photo :)

Jay and I heard a poorwill on only one of our nights in the sawtooths in that area this past week. that's less than we'd been hearing at our other campsites.