American Kestrel Partnership : Nestling mortality and the death of a chick in the KestrelCam nestbox

The struggle to raise young is difficult for wild animals, especially for birds of prey.  For raptors, it is not uncommon for the youngest chick in a brood to die. In fact, a study of American Kestrels in Saskatchewan showed that the youngest bird survives to fledge in only roughly 68% of broods. Many have noticed that the youngest member of the brood in the KestrelCam box died last evening and was then eaten by its siblings. Although we hate to lose a chick, we realize that this is natural for wild animals and that raptors in particular have evolved this behavior to survive in a rough world. Last year, the youngest of five chicks also died in this nest box.

We’ve gotten several questions regarding how the chick died. Some have suggested that perhaps it was siblicide – the killing of one chick by another. Although siblicide is common for many raptor species, it is less common in falcons. Further, a review of the footage of the feeding event didn’t reveal a struggle before the death of the chick. Others suggested that perhaps the chick was a victim of brood reduction due to a lack of food. Brood reduction is when a parent selectively feeds the largest members of a brood when food is in short supply.  It is certainly possible that the youngest chick starved, although we’ll probably never know for sure how the chick died.

Many questions also regarded the chicks feeding on their dead sibling. Although it can be hard for humans to imagine, cannibalism occurs among wild animals, including raptors. The study of American Kestrels in Saskatchewan suggested that dead chicks were eaten by their parents and siblings more often when food was in short supply. One of the things we all love about the KestrelCam is that it shows us aspects of nature that we rarely get to see. It shows us the great amount of work that the parents put into raising their offspring. Last night we saw just how hard the struggle to survive is for wild kestrels.

For more information about mortality of American Kestrel chicks, check out the study in Saskatchewan by Karen L. Wiebe, available here from the Searchable Ornithological Research Archive (SORA).


Sharon Hayes's picture

Are the chicks banded? I thought I could see a leg band on the bird last night.

Thanks for keeping us informed! Sharon

TKE878's picture

There was clearly a band on the leg of the dead/eaten chick.  I also saw one on the male as he stretched.

Delorahilleary's picture

Indeed they are!  We quickly banded all five chicks on Monday of last week.

dispatchercheri's picture

The day before I observed three of the chicks fighting and it appeared that the two larger ones were picking on the smaller one. I was not surprised to see that the younger one had died. 

TKE878's picture

I was curious if the carcass of the dead chick was removed, or if it was totally devoured by the others.  I no longer see the legs.

Delorahilleary's picture

It was quickly eaten by its three siblings as soon as it stopped moving, it seems. We did not remove anything from the box.

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Posted in American Kestrel Partnership by American Kestrel Partnership 4 years 4 months ago.