Rosyfinch Ramblings
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January 2012
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Keeping eyes on an eagle nest
Filed under: General, Birding & Outdoors, Florida & SE US, Birding "Patches", Bald Eagle Nest
Posted by: Ken @ 6:37 am

This is the fourth winter that Mary Lou and I have been monitoring a Bald Eagle nest that is located only about 1 1/2 miles from our South Florida home. So far, they are known to have successfully raised eight eaglets since the spring of 2008. In a previous post we provided an overview of this, the first active Bald Eagle nest in Broward County since the 1960’s, before DDT was restricted.  We organized a team of eagle watchers to monitor and help protect the nest, and I serve on a City of Pembroke Pines Bald Eagle Sanctuary Steering Committee that has helped develop changes in planning documents and recommended an ordinance to better protect this and any other nest from disturbances.  

We visited the eagle nest Monday morning January 15. The first egg was laid on or about December 11, and this was the day we expected it might be hatching. When we arrived at about 8:30 AM we could see the top of the head of one adult bird deep down in the nest. The incubating adult tends to sit a bit higher, “tenting” any newly hatched chick, so we took this to be a sign that the first egg has not hatched.

The bird did move about, but never stood up during the hour or so that we observed the nest. A second adult flew and roosted on the horizontal limb above the nest, began calling excitedly and looking down at the nest. We do not think the bird on the nest called back. Our experience has been that such a  change in behavior suggests that an egg may have indeed hatched.

Then the adult flew off to the east, only to circle behind the nest and take a roost in the dead Melaleuca grove west of the nest.   It appeared to be the female, though we could not be certain.

A Red-shouldered Hawk was roosting just west of the nest tree.

A Great Egret flew over the nest, and I stitched together 15 sequential images. Here are a few.

Two days later (January 17), the incubating bird was more visible. Is it possible that she is indeed  “tenting” a chick that has hatched?  No other adult was in sight as we watched from about 12 noon to 1:00 PM.

Here, the adult (female?) is peering down underneath her– is she rearranging eggs or tending to a hatchling? Her head and sometimes part of her back and tail remained visible the entire period of observation, something that had not happened since the eggs were laid.

On January 22 we were treated to the sight of a small falcon that flew in and roosted just west of the Bald Eagle nest tree. It made two flights out and returned to the same tree. Its wingbeats were energetic and it flew fast and directly. It was heavily streaked and its profile showed its head to be smaller than an American Kestrel’s. It had one whisker stripe and no strong face pattern as seen in a female kestrel. It appeared to be an immature Merlin. Photos are from about 200 feet, so they are not very sharp.

Mary Lou and I continued watching the nest almost every day, and saw definite signs that the egg had indeed hatched, such as the presence of prey in the nest and feeding of one or more eaglets. On Thursday morning (January 26) we watched from about 10:30 until about 11:15. When we arrived the female was roosting on the right edge of the nest, looking about and appearing restless.

Mary Lou correctly guessed that she was awaiting a food drop, as within a few minutes the male flew in with a medium sized fish that looked like an exotic Mayan Cichlid, a common fish in local lakes.

The pair called to each other and touched bills in a sort of recognition ritual, and the male (on the left) flew off.

The female tore at prey and fed one or more eaglets. We still could not see the eaglets over the rim of the nest– we assume the nest cup is a bit to the rear. In past seasons the young have appeared over the nest rim at between 12 and 23 days of age. If our behavioral observations are correct, hatching occurred on January 15, and the first eaglet would be 11 days old this day.

Turkey Vultures must now be smelling the prey, as a couple of them circled several times close around the nest tree. In the past we have seen the eagles chase them off.

On Friday morning (January 27) an adult was quiet on the nest and there was no sign of its mate as we watched for about 3/4 hour from 9:30 to 10:15 AM. The oldest chick was then about 12 days old. A front page story about Florida’s urban eagles appeared in the paper that morning, with a quote and a slide show of some photos of me and other eagle watchers.

Of interest, a male Northern Harrier flew over the nest area. Mature males, which are gray and white with black wingtips, are outnumbered 8 or 12 to 1 by the larger brown females and immature birds, so it is a treat to see one.

A flock of Fish Crows chased a colony of Monk Parakeets away from their nest on a high light pole across the street from the eagle nest. I thought they were looking for eggs or young birds to eat, but instead they stole twigs, presumably to use on their own nests. Fish Crows can be predators on the very young eaglets.

Saturday (January 28)  morning we checked the nest, hoping to see one or more chicks peeking over the rim of the nest. The first-hatched should be about 13 days old. At 8:15 AM the female was quiet and rather low in the nest, so we assumed that the chick(s) had been fed and were probably sleeping. We note that when a food drop approaches the hen stands high and gets restless. Therefore we went birding at Chapel Trail and returned at about 9:30 to find the male roosting in the nest tree on a horizontal limb above the nest. We had probably just missed the food drop.

Note the slimmer and more tapered body of the male. His bill also appears to be a bit less massive than that of the female. This year he does not have the dark streaks on the outer tail feathers that helped us distinguish him the past two seasons. The power lines just in front of the nest are one of the hazards faced by urban-nesting eagles.

The female was active, tearing at prey and feeding the the chick(s). I think we had just missed a prey drop. About 10 minutes after our arrival the male flew away low to the west.

The female remained on the nest for less than 5 minutes before flying over to roost on a Melaleuca snag just to the west. 
She is noticeably larger and rounder than the male.

She flew back to the tall pine just west of the nest and roosted a few minutes, then settled back on the nest. The nest was left unguarded for about ten minutes. This rarely happens when the chicks are less than two weeks old. See the Eagle Milestone spreadsheet  which chronicles observations over the past four breeding seasons (PDF). This was the first time this season we witnessed the nest uncovered and without a lookout nearby.

For updates on observations of this nest, visit the Pembroke Pines Eagle Nest Watch FORUM at this link.