GHO Nest Fails

by Carl Strang

Two years ago, Mayslake Forest Preserve’s great horned owls nested in a hollow in a dead willow stem.

There is nothing like the glare of an incubating great horned owl. Daggers.

A March storm ended the venture, snapping the nest tree off at its weakest point – the nest cavity – and killing the young. A new effort cannot be started so late in the season, and so they waited for another opportunity.

Last year the owls were around all season, but did not nest on the preserve. The male’s behavior led me to suspect that they had a nest in the residential neighborhood south across the lakes, but if so, the loud contact calls of the young were not to be heard all summer on the preserve.

We did have a successful raptor nest, though.

Here is the single red-tailed hawk nestling on the verge of fledging, last June.

In mid-January I saw that a great horned owl was hanging around the red-tail nest. Sure enough, on January 27 incubation began.

She was steadfast on the nest through the major storm of February 1-2.

The typical incubation period for great horned owls is 30 days, so the first egg’s expected hatch date was February 26. In the cold weather one does not expect to see the tightly brooded young for a while.

March 8 was relatively warm, so it was not too surprising to see the nest without an adult.

I thought I saw something pale at the left edge of the nest. The downy head of an owlet? I wondered.

March 9 was cold, however, and the continued absence of the mother bird gave me a sinking feeling. Yesterday I brought my spotting scope. The pale spot on the nest was just a leaf. The nest was abandoned. I went to the tree, but found no dead owlet beneath, nor any sign that a person might have been there in recent days to cause a disturbance.

My best guess is that the egg or eggs were infertile. The owl gave up when the hatch was 10 days overdue. Perhaps this pair is old, and their reproductive years are past. In any case, they are done for another season. This is why they live so long: it’s difficult to raise a successful, surviving young great horned owl.

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2 Comments

  1. March 15, 2011 at 5:59 am

    […] to build their nest last year. This is the nest that was taken over by the great horned owls in this year’s ill-fated nesting attempt. Looking over my notes, I see that the red-tails telegraphed their eventual nesting area by […]

  2. March 22, 2011 at 6:10 am

    […] Forest Preserve’s great horned owls are not raising any young this year, as I mentioned recently. They still are around, however, despite that setback. The eggs apparently never […]


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