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The Canadian Peregrine Foundation - Endangered Species Bulletin

The Canadian Peregrine Foundation

Eagle Vision
Placentia Bay's birds of prey help moniter changes in ecosystem
Mon, August 21
Barbara Dean-Simmons
The Packet


Itís not an easy matter to "drop in" for a visit with an eagle.

The nests of these birds of prey are usually located on cliffs that drop into the ocean on a vertical incline of nearly 90 degrees.

So for Joe Brazil, senior manager of endangered species and biodiversity with the Department of Environment, getting information about the eagles that live on the islands of Placentia Bay has meant a lot of trudging through dense forests to the edge of the cliffs, to climb down into nests for a quick inspection of the baby bird and its home.

On this particular day in late June, with environment minister Clyde Jackman tagging along, Brazil is able to explain the logistics, and the challenges, involved in banding eagles.

The first stop is at a nest a few minutes outside North Harbour.

Forestry officer Ed Loder pulls the small boat alongside the rocky shoreline, allowing us to climb out onto the rocks and make our way up the steep incline.

Forestry officer Shawn Avery leads the way. The Department of Natural Resources also plays a role in the monitoring of eagle populations. For the past couple of years Avery has been making note of eagle nest sites in the Trinity Bay area, helping Brazil add to his database of knowledge.

Avery leads the way through dense brush, across a couple of small bogs and to the edge of the cliff

A few feet below us, in a nest that seems to be balanced precariously on a rocky ledge and whatís left of a dead tree, a juvenile eagle grows edgy.

Mother eagle soars overhead emitting a high-pitched call. Brazil explains the mother wonít attack us. The keening noise she is making is a bit of eagle bluffing. Sheís trying to lure the intruders away from the nest site by making them think thereís something more interesting over there, where sheís flying.

Brazil and Avery quickly decide itís not wise to try to band the young eagle in this nest.

His wings are almost fully developed, but he cannot fly. Thereís the risk that if they descend into the nest, the young bird might jump to its death.

We watch for a moment and then head back to the boat. Still, it gives idea of the challenges Brazil faces in getting close enough to a young bird to place an identification band on its leg and inspect the nest.

Over the years heís climbed up, down and out to 120 nests to band young eagles.

"Iím probably getting a bit too old for this now," he jokes, as he stops to catch his breath at the end of our trek.

 

Collecting information

Brazil has been studying the Placentia Bay eagles since the first official population count of these birds was conducted in 1983.

"That was just a preliminary check just to see what logistics would be involved in surveying Bald Eagles," he explains.

Prior to the surveys the department conducted an "Eagle Watch Program" encouraging people around the province to report sightings of the birds.

"Based on that information we came up with a projection that Placentia Bay probably had the higher density of eagles."

Most of the reports of eagle sightings, he adds, were from fishermen who were encountering eagles practically every day when they were on the water.

In fact, by the time the program hit its stride, there were over 400 people ó who regularly reported eagle sightings ó on the departmentís newsletter mailing list.

"So for the most part, most of our early data came from sightings. Most of the reports were just sightings but the real gems were the people who actually knew of a nest site."

Up until then there was very little information on the birds of prey.

The department was also wondering whether problems with the cod fishery ó the federal government declared a moratorium on the south coast in 1992 ó would impact the eagles.

Brazil says they knew enough about eagles to know that they were very dependent on fish.

The question was whether the birds of prey would be impacted by what was going on in the ocean environment.

In fact, in the 1980s eagles were listed as an endangered species in many parts of Canada and the United States.v

"Across North America there was a very large concern over the future of bald eagle populations. And when you went to the literature, there was often a black hole in terms of information about eagle populations for Newfoundland and Labrador."

Brazil and his counterparts figured they could fill in the gap by conducting a census of the birds and carrying out some studies.

 

New territory

Brazil was blazing new territory.

"There were never any dedicated surveys for Bald Eagles in this province, except in some instances where there was a development being planned. For example when they were looking at the Churchill Falls development, there might have been some surveys for birds of prey. And in the mid 1970s biologists did some surveys of bald eagles in the interior of Labrador. And that was the only information we had."

The other thing that makes Placentia Bay a unique area for study, adds Brazil, is the industrial growth in that region.

"Itís probably one of the most impacted, or potentially impacted, bays we have in the province. And eagles are, in many respects, great bio-monitors. By monitoring the health of eagle populations you are actually able to learn a little bit more about the health of the ecosystem as a whole."

1983 was basically a matter of putting themselves and their equipment to the test to see how much information they could gather with the resources they had.

That year they spent a couple of days on Merasheen Island and traveled around the island in an 18 ft open boat.

"If a fisherman had reported a nest site in the area, we were checking to see if it was there, to validate that report.

"We were pleasantly surprised," he adds. "Just about every site that had been reported by a fisherman turned out to be an eagleís nest."

They found nearly a dozen nests.

 

Long-term picture

Eagles require long-term monitoring to get an understanding of their habits, notes Brazil.

While the birds prefer to use the same nest all the time, they sometimes abandon a nest for a year.

"They are not much different from other wildlife populations. There are peaks and valleys in (population); it depends on their local environment. Thatís why long-term data sets are incredibly important in monitoring wildlife populations."

Since those early surveys, Brazil and field workers from the environment and forestry departments have been making the trip to the islands twice a year to check on the birds.

The permanent survey area includes the Merasheen Island and Long Island, the islands adjacent to the Merasheen Islands and the coastline on the Western side of the bay.

Although theyíve missed a year or two of surveys due to logistical problems, the surveys have been done at least once a year, surveying about 400 km of coastline each year.

"If we have the resources we will do two surveys. We will do our early nesting survey, thatís when the females are sitting on the eggs and it gives us an idea of how many sites are occupied. Then we go back in late June to resurvey the same route and we can count the chicks to see how successful the females were in having a brood."

Overall, says Brazil, the eagle population in Placentia Bay has been relatively stable.

"Weíre averaging about 20 to 30 nest sites within our study area.

"For the most part, during our surveys we will only see adult eagles." It takes five years for an eagle to become an adult, for its white head and tail to develop.

"What was most interesting this past year, 2005, was the first year we saw any significant numbers of immature birds Ė eagles aged 1-4 years old. And the number of nest sites we saw was 17-18."

As the boat coasts past the shorelines of Long Island and Sound Island, each of us scans the tree line for a glimpse of an eagle.

The reward for being the first to spot a new nest site is to have that point of land named in your honour in Brazilís field notebook

On this day, Brazil adds Barbís Point and Jackmanís Point to his notes.

 

Future work

So far, only a half dozen of the 120 eagles Brazil has banded over the years have shown up beyond Placentia Bay.

This province participates in an international program that tracks the migration patterns of eagles.

Different coloured bands are used to distinguish various regions ó red for the island of Newfoundland, yellow for birds from Quebec, green and blue for New York State.

Eagle feeding stations are set up throughout Nova Scotia and all along the Eastern Seaboard of the United States.

"People with spotting scopes monitor these stations. If they see a bird with, say a green and blue band, they know it is probably from New York State.

"We were banding birds here with red bands stamped with white numbers. Not one of them ever showed up at one of these feeding stations," says Brazil, adding the stations are a "magnet" for bald eagles so if a bird was flying in the area it would be drawn to the feeding station.

Based on the information from those stations, Brazil says there is a strong assumption the bald eagles from Placentia Bay donít migrate.

Itís important to know that, he says, because if the eagles do stay in Placentia Bay year round, it means that population would be vulnerable in particular scenarios.

Given the amount of tanker traffic coming and going in Placentia Bay ó itís the busiest shipping lane in Eastern Canada ó "if you have a major calamity occur (there) you could actually wipe out the eagle population in that entire bay."

The birds may be moving over to Fortune Bay for part of the year, he says.

New technology may help determine whether thatís the case.

The next step, explains Brazil, is to install lightweight radio transmitters on some of the birds. Through global positioning technology, satellites in space will track the birds as they fly, allowing Brazil to monitor their movements on his computer in his Corner Brook office.

vThe solar-powered transmitters can last for about two years, he notes. That would give him quite a lot of data regarding the birdís movement. He hopes to be able to add that technology to his survey work over the next couple of years.

 

Important information

The benefit of knowing so much about eagles, says Brazil, is that these birds are at the top of the food chain.

"They could be biomonitors of the health of our ecosystem," he says, similar to how studies of peregrine falcons proved the dangers of the use of DDT.

"If it wasnít for people tracking peregrine falcon numbers back in the 1940s and 50s we could have children today full of DDT."

Thatís why the study of these birds is so important.

"They tip us off about things going on in our natural world."

Knowing about wildlife ó whether itís eagles, pine martin or moose ó is essential for anyone who is in the role of a wildlife manager.

"You have to keep in touch with the creatures you are responsible for, providing advice and management for. If you donít know the environment they live in how can you walk into a meeting to defend them?"

In addition, he says, "thereís nothing quite as thrilling as sitting in an eagleís nest."


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