Vancouver: The Urban Eagle Capital of World
Sunday, January 22 2006 @ 07:22 PM EST
Contributed by: davidh
Vancouver Area Eagle Nests: Life cycle summary.
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More than 150 pairs of Bald Eagles nest within the greater Vancouver area
The Urban Bald Eagles of greater Vancouver British Columbia and the Fraser Valley:
During my 1960s studies, only three pairs of Bald Eagles nested in the greater Vancouver, BC area——one pair in the city’s spectacular Stanley Park, and the other two across the water in Lighthouse Park in West Vancouver and a pair on the Indian Reserve at Dollarton. Another pair kept unsuccessfully trying to nest on the University Endowment Lands.
Vancouver Now the Eagle Capital of the World
Today over 150 pairs nest and raise young in the same Greater Vancouver area——many nesting no more than 50 feet (16 meters) above busy streets and beside occupied houses. The bald eagle has become a city dweller of spectacular proportions. How did this happen?
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The Urban Eagle continued ....
Since we did not band the city nestlings the following hypothesis is conjecture but very probable. The city-bred eaglets were obviously acclimated to seeing people below and around their nest. Obviously these people were not harmful, just part of the landscape. As these eagles matured and looked for suitable nest sites they sought out a nesting site like the one in which they had been raised. The city parks and adjacent riverways and farmland were perfectly acceptable habitats with lots of food and these eagles simply chose the largest trees. I suspect all the greater Vancouver City eagles are descendants of those few nests in Stanley Park, Lighthouse Park and along Dollarton on the north shore. How much fun it would be to genetically test this hypothesis.
Nesting in and around cities and adjacent farmlands does however present some problems for the eagles. An eagle’s nest can be 5 to 8 feet across (1.5 -2.5 meters) and weigh 500 to 2000 or more pounds (1/4 to 1 metric tonne). It takes good solid mature branches to support such a nest and many eagles fail nesting because the nests blow down or break the tree limbs. While in many remote areas the eagle might choose 200 year old mature trees , 150 feet (50 meters) or more high in height, in and around Vancouver there are few such tall trees with suitable supporting branches. The result is we have a population of bald eagles adapted to nesting in very low trees and very close to people.
Many private persons with eagles nesting in their yard rightfully are quite protective of these spectacular neighbors and do not encourage too many people around the nests. On the other hand many of these nests are very obvious to the passerby and can be readily observed. Many nest in the city parks and treed lots. We just caution respecting both the birds and nearby neighbors by not observing from too close or overstaying your welcome.
Bald Eagles in the Vancouver area, of southern British Columbia set up their territories in late September or October through January and February when the area is also occupied by hundreds of wintering eagles from more northern areas. From early February through March the two to three eggs are laid. Hatching starts early to late April after approximately a 36 day incubation period. The young stay in the nest about 11˝ to 12 weeks. Shortly after fledging the young are abandoned by the parents. The fledged chicks independently head for northern rivers where the earliest fish runs occur providing easy food for the inexperienced young.
I have never seen adult eagles feeding young outside the nest. The baby fat of the nestlings is undoubtedly their food reservoir until the bonanzas of the salmon rivers are reached — sometimes after a 1000 mile flight. . In fact, all the nestling birds, the parents and non-breeding birds that have stayed in the area during the summer leave the area by late July or early August. In late September early October the adults return to stake out their territory and make nest repairs. Mating takes place from the day of their arrival on their territory and throughout the nesting season.
Vancouver urban habitat is surprisingly productive. The Vancouver area nests produce almost twice as many young eaglets per nest as the wilderness areas of outer coast. While our suburban area abounds with coastal bays and food rich intertidal areas, the city is also bisected by a myriad of little streams and the marsh and delta areas of the Fraser River. Rats and muskrats abound around the city and are favorite prey. The bald eagle while a capable hunter prefers to scavenge. Every morning at daylight the eagles can be seen road-hunting – looking for the nights road killed rats, cats and bunnies. They also pick up the road killed crows and during that week of the crows vulnerability, the week the young crows are branchers and not quite flying, they are heavily preyed upon by eagles. The bald eagle has settled in to become one of our commonest breeding birds. An unusual wilderness species that, like the crow, racoon, coyote and Canada goose, have become urban dweller.