Black flies

Things have taken a disturbing turn in the last 24 hours. Yesterday I was watching a nest and the female jumped up and flew off the nest repeatedly to fly loops, leaving eggs unincubated for 5-10 minutes or so at a time. I found this odd. I was standing outside with my scope on a tripod and was aware that there there was a sudden increase in bugs. They were crawling all over my scope , my head, flying into my eyes and nose, but I did not feel like I was getting bit. The previous two days it was bug free and pleasant to be out there in the field. I noticed the female was shaking her head almost constantly. She repeated this pattern of flying off many times. I finally left and proceeded to another nest. At this nest I found no one on the nest at all. Oh dear. Then the female finally returned, sat down in incubating posture for a few minutes and the suddenly jumped up and flew off. She did this over and over, flying loops before returning to the nest briefly. For over 90 minutes this continued. At one point she was gone for 20 minutes and came back with blood on her neck. I hope it was fish blood. She never stayed in the nest for more than five minutes at a time and was shaking her head constantly. I started to connect the dots between the observed behaviors on these two nests. Then last evening I got a report from someone watching the Arboretum Cam nest. Female would not stay on the nest. She was shaking her head constantly and you could see bugs swarming the nest. When I went to bed, the eggs were still uncovered. This morning the male was in the nest. Then I received another report of a female that would not stay on the nest. The monitors are very concerned, as am I. This appears to be a new hatch of black flies which are tormenting many ospreys. I don’t remember it ever being quite this bad, tho a few years ago, we had a huge hatch that caused a chick on the Arboretum nest to jump to its death prematurely, to escape the flies. This is coming at an earlier time this year when we have newly hatched chicks, or eggs about to hatch. The timing could not be worse. I have been observing today that some nests seem to be unbothered......those that are further away from lakes and who are higher up. On some very tall cell tower nests, I see a definite breeze and no head shaking at all. I am afraid that some nests may fail if the adults literally can’t stand to be on the nest. Black flies live for about three weeks, so those late hatching nests may be the lucky ones this year. This all may be related to climate change and the heavy rains we have had recently. It’s very hard to watch these tormented ospreys, but there is nothing we can do, but observe closely, document carefully. This is how we learn, and this is why we keep monitoring these nests for so long. Ospreys are an indicator species so the health of their population reveals much to us about the health of our environment. So monitors, pay close attention to behaviors. Head shaking and agitation may seem like a small thing but it may turn out to be critically important. Watch closely. For me these seem like dramatic changes in behavior. It’s even important to report the lack of head shaking! It may help us figure out which nests are more vulnerable to black flies.

We have had a number of nests fail in recent days....adults are just suddenly gone. Could it be black flies that drove  them off the nest? Time will tell. As I continued to make some rounds today, many nests seemed to be fine, or only slightly bothered...not enough to cause them to leave the nest. The breezes picked up as the day progressed. That may help the situation. Fingers crossed for this to be a minor blip, but I encourage all Osprey nest monitors to pay close attention to the head shaking and how long adults are off the nest. Include this info in your reports.

Think good thoughts for our winged friends!