I have a nesting pair of kestrels in a box that we have a camera in. She laid five eggs starting on April 24th. All was fine, both parents have been sitting on the eggs, but mostly the female. We have been waiting for the eggs to hatch and when I looked yesterday there was only 4 eggs and there and no evidence of the 5th?? It got worse today as there are now only 2 left?? Again there is no evidence of any egg shells or chicks. I have yet to go back on the DVR and review what happened, but is that unusual?? I've had a nesting pair of kestrels here before and I know they fledged two last year. The camera didn't work last year so I don't know if they started with more than 2 eggs I hope that these 2 make it. Anyone have a similar experience? I don't think that it is a predator as the box sits on top of a 20' pole off by itself and I've watched the kestrels chase away any other hawks or birds. Please tell me that this is somewhat normal.
Comments:
My guess would be that a
My guess would be that a predator got to the eggs, which happens sometimes in nature. I'd be curious what your video records show!
If it is indeed a predator, you can install a predator guard this fall, for next year.
I will let you know what the
I will let you know what the DVR shows. I can't imagine what could get in there and eat the eggs. Have kestrels been know to cannibalize still born or damaged eggs? Hopefully the tape will tell what happened. Thanks
I reviewed the DVR and it
I reviewed the DVR and it appears that the female ate the two eggs during the overnight hours between 8:00 pm and 4:00 am. I say it "appears" because when the birds are in the box the view of the eggs is blocked by the birds. The female went in the box at dusk as usual and sat on the 4 eggs. Around 3:00am she got very restless and was squirming all around and it sure looked like she was eating the egg. At sunup there was only 2 eggs left. No predator came in the box all night. That was during the overnight hours of May 24 into May 25. There are still 2 eggs remaining today, May 27. Has anyone ever seen anything like this?? Very strange
Anybody???
Anybody???
Could there be a shortage of
Could there be a shortage of food, so instinct kicks in for survival. Thus is why the female may have consumed the eggs. Nu-Sun Cinema
Hi there,
Hi there,
Thanks for this information; if you'd be wiling to share it, we sure would like to see the recording too! You can send it to schulwitz.sarah@peregrinefund.org. I have not found any published paper that provides solid evidence that American Kestrels eat their own eggs. But that does not mean it does not happen. Technological advances during the past two decades have allowed recordings like yours to shed light on what used to be a mystery (i.e., the minute to minute happenings inside a nest box). With more cameras on nests, we could test the hypothesis that Kestrels indeed cannibalize eggs and the recordings would provide the solid evidence one way or the other.
You may be interested in the following paper I found that describes cannibalism in American Kestrels by parents and siblings:
Bortolotti, G. R., Wiebe, K. L., & Iko, W. M. (1991). Cannibalism of nestling American kestrels by their parents and siblings. Canadian Journal of Zoology, 69(6), 1447-1453.
The paper describes presumed cannibalism of AMKE chicks and possibly eggs. More hard evidence (i.e., partially eaten chick left in box following a stay by parents only with no evidence for a predator visit) was presented for cannibalism of chicks than for eggs. This may be of interest to you. Of note, the chicks that were eaten were often the latest hatched, lowest weight, and/or otherwise weakest. The parents were often in poorer (lower body weight) condition and/or prey were not abundant. Had this study used nest box cameras, perhaps they could have gleaned even more information regarding the biology of this species.
Send me an email and I'll send you a PDF if you cannot get access to the paper. Schulwitz.Sarah@peregrinefund.org
Sorry we can't give you an explicit yes or no. However, this is the exciting thing about science.....when we don't know the answer to a question, we can design a study to try to find the answer!
Best wishes,
Sarah
Could there be a shortage of
Could there be a shortage of food, so instinct kicks in for survival. Thus is why the female may have consumed the eggs. Nu-Sun Cinema
I'm working on getting you
I'm working on getting you the video. It was too large to send via email. It was taken with my iPhone from the computer screen. Today, June 4th, the first egg hatched just a couple of hours ago. Is it normal that she still covers the new chick just like an egg? I did catch a glimpse of the chick and it appears to be alive. In the meantime I will try to get you that video of her eating the eggs.
There is no shortage of food
Great thanks so much! Yes, it
Great thanks so much! Yes, it is normal behavior for the female to continue incubating chicks. At this stage, chicks are still unable to thermoregulate, so you'll see the parents incubating for a bit longer. Eventually, (if there were five chicks) the chicks would grow so much that they wouldn't fully fit under the parent and you'd see little puffs of chicks poking out from under the parent.
Just a short update. Only one
Just a short update. Only one chick hatched. One egg still in box. The last egg was laid on May 2 so I'm assuming that this one is NG. Why she would have eaten the three other eggs and not this one is odd. The one glimpse I got of her eating the other eggs looked like there was yoke in the egg, not a developed chick like it should have been after 24 days. I figured that somehow she knew those were unfertilized and were bad. The chick is now 11 days old and doing fine. The female is very attentive and feeds the chick often. When I watched the Kestrel Cam on your website I noticed that the male participated in feeding and keeping the chicks warm. What is strange with this pair is that since the chick hatched the male hasn't been in the box. I've seen him bring her food that she tears up for the chick but he never goes in with the chick. Odd??
Hi there, thanks for this
Hi there, thanks for this update. As long as the male is present to bring food to the female, there isn't much to worry about. The difference in behavior is part of natural variation exhibited by this species. Additionally, the Bosch KestrelCam nest that we broadcast had five chicks in it, presenting a very different workload for the parents. With only one mouth to feed in your nest, my guess is that this slightly influences the behavior of the parents. Be sure to enter your data into our website so your kestrels are represented!