June 11, 2019 at 10:03 pm #7436
Have any of you had nestlings die from blow fly larvae? For about 5 years we had our nestlings banded and when that happened the bander sometimes checked for this, but the nestlings were always okay.
This year I took a picture when the nestlings were 5 days old and they looked good. This box is where I can observe from inside our home, so I could observe if the parents were feeding the young and if so I figured they were probably okay. One week later when the nestlings should have been 12 days old, I noticed the parents were not feeding them. I checked the box and found 4 dead and one missing. When I took out the nest I discovered the larvae. It appeared that the nestlings died at varying times. And I suspect the missing one was taken out of the box by the parents. One was more deteriorated than the others and one had feathering that looked like it belonged to a more mature nestling. I think at the end the parents were only feeding one nestling.
I am trying to find information that might help with this problem. The Papa Blue has stayed close to the box but I have not seen the Mama since the day I cleaned out the box. If they use the box again I am wondering what precautions might be taken.
Willamette Valley, OregonJune 13, 2019 at 9:09 pm #7440dogsandbirdsModerator
Yes they can kill nestlings if there are enough of them.
Here’s lots of info: http://www.sialis.org/blowflies.htm
Atlanta, GAJune 14, 2019 at 1:56 pm #7446
Thank you, Gin. I have looked at that site and actually a photo on the Sialis.com helped me identify the culprits. Sialis is my favorite bluebird information site. However, I gather from another source that the jury is still out on these parasites. There seems to be disagreement on how dangerous they are and how to handle to problem.
So I am hoping to hear from people that may have personally observed the effects of blow fly larvae. This was a first for me and I hope to learn more about how dangerous they are as well as how best to prevent them from invading the nest.
Willamette Valley, OregonJuly 6, 2019 at 12:21 am #7546tamseaModerator
On the purple Martin groups we recommend sprinkling a 1/4 tsp of 5% Sevin under the nests. This works on mites and I bet it would work for blowflies.
TammyJuly 20, 2019 at 10:51 pm #7614
Following advice on a bluebird facebook site, we placed Diatomaceous Earth about an inch under the nest cup after the first egg was laid in Mama Blue’s second clutch. I hope that works because now Mama Blue’s second nest has six hatchlings. I will likely check these more often, but hope I will not need to intervene. From what I have read, if an infestation is severe, it might be necessary to give the bluebirds a new nest. But this box has been used every year since 2012 and this is the first year this happened, so I would like to think it will never happen again.
Willamette Valley, Oregon
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