Bald Eagle Nesting Season Is Beginning

 by Mark ‘Bird’ Westall

It is now October and Sanibel’s bald eagles will start laying eggs before long. I will be watching one particular nest with an “eagle eye,” so-to-speak. Last spring, in the middle of nesting season, I worked in cooperation with the staff at the SanibelCaptiva Conservation Foundation (SCCF) and the Lee County Electric Cooperative (LCEC) to erect an artificial platform specifically designed to attract the eagle pair at SCCF’s West Sanibel River Preserve.

This pair has had a tough time of it lately. Their original nest tree had been accidently killed several years ago because when the habitat crews went onto the preserve to poison the invasive Australian pines on the property, they saw no nest in the nest tree and did their job.

Unfortunately, large eagle nests fall out of Australian pines quite often because this species of tree makes a terrible place for an eagle nest. These exotic “pine”trees satisfy the height criteria that the

eagle pair is looking for, but the shape of an Australian pine is not usually conducive for the nest to survive very long. The next time you get a chance, compare the shape of an Australian pine to that of a

slash pine and you’ll see what I mean. Therefore, the birds are always having to rebuild their nests if their first choice is an Australian pine.

After realizing their honest mistake, the staff at SCCF immediately called me to see if I would be interested in building an artificial nest in the dying tree, one that would be able to stay together as long as the nest tree itself remained standing. Of course, I agreed to do the project and was proud to say that, even though the nest tree was no longer alive, the nest looked completely natural.

The artificial nest was approximately 70 feet up in the air and it was quite exciting putting it together. The day of the construction was slightly breezy and every once in a while, I had to wait for several seconds to work on the nest as the wind would drift the cherry picker and tree too far apart for me to reach the nest.

Thus built, this artificial nest in the dead Australian pine was successfully used for several years. Unfortunately, the dead tree finally fell during a fall cold front last year and the birds have been trying to

find a suitable new site ever since.

When I first began serving on Lee County’s Bald Eagle Technical Advisory Committee (ETAC) way back in the mid-1980s, there were still many people sometimes even from the scientific community) who did not believe it was possible to get bald eagles to utilize artificial sites.

I said “Hogwash!”

The problem was that people have a difficult time thinking like an eagle. It was easier for people to accept the idea that ospreys would nest at artificial sites because humans accidently were building

structures that satisfied the needs of the ospreys. We put up utility poles, nice, big houses with beautiful, high chimneys, etc. The ospreys would look at these developments of man and say, “I always

wondered why humans existed; now I know. It’s to build wonderful nesting sites for us!”

I have been asked many times by owners of an osprey nest on their chimney, “Why don’t they nest out in the mangroves of the refuge? There are plenty of trees there. Isn’t that where they’d

rather be?” Today, because of Hurricane Charley, there actually are a lot of potential nesting sites in the mangroves since the upper half of the canopy was mutilated and many snags perfect for nest

building were left standing. But before Charley, the canopy of the mangroves was fairly uniform and nesting sites were limited.

Just because there are lots of trees, does not necessarily translate into suitable habitat for the wildlife. Once the ospreys showed us that they would nest on manmade structures, we were then able to

use our intelligence to purposefully build nest structures to satisfy that need.

The situation for bald eagles is different, however. We do not “accidently” build human-oriented structures that satisfy the needs of that species. Eagles want to have their nest at – or above – the

surrounding canopy, just like ospreys. But in Florida, eagles prefer to have plenty of shade over the nest to protect the young from the searing heat. Ospreys do not usually need this shade because

the female osprey stays on the nest and uses her body to create shade. With bald eagles, both parents habitually leave the nest and forage for food, leaving the young chicks vulnerable to heat exhaustion.

I noticed these criteria in bald eagle nest site selection in Florida and have been successful in getting seven pairs now in Lee County to use artificial nests. Granted, most of those artificial nests where situated in natural trees, but one nest on Hogan Key, up near Boca Grande, was a totally free-standing structure.

In March of this year, we erected the new, totally artificial-looking platform and, hopefully, it will eventually serve as a more permanent home for the eagles. But before we could erect the new platform, and after several attempts to find a suitable natural nest site in the area, the eagles began putting sticks in another dead Australian pine not too far away from where the new platform eventually was erected. From this new natural site, they watched as the platform was erected.

Bald eagles, like ospreys, are pretty tenacious about sticking with a nest site once a choice has been made; though they may have a few backup sites. Something usually has to happen to that nest site before the pair will move to another potential nest site in the nesting territory. Possible disturbances include nests falling out of the tree, great-horned owls commandeering the nest, human disturbances, etc.

Therefore, I suspect the eagles will continue putting new sticks in the recently chosen dead Australian pine. Unfortunately, this nest site is just as unstable as the other sites that were experimented with last fall and winter. So far, the nest is only partially built and I suspect that a fully developed nest will not

survive. All we can do now is watch and hope. At least, if the current natural nest falls apart, the eagles will have something more solid to move to this time.

Let’s keep our fingers crossed!

A former city council member and mayor, Mark “Bird” Westall has owned and operated Canoe Adventures, Inc. on Sanibel for over 33 years. Visit www.canoewithbirdwestall.com for more information.