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Captive Breeding Program for Northern Spotted Owl

Conservation & Preservation
A habitat for one of Canada's most endangered birds is taking shape in Langley, British Columbia.

A few months from now, owls will hunt prey among tree trunks and saplings in a forested region near Fort Langley.

They will be one of the rarest birds of prey in the world, the Northern Spotted Owl.
The birds won't be living in the wild, however. They'll be enclosed in a large, brand new aviary being built on the grounds of the Mountain View Conservation Centre.

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Chehalis River Estuary Above Ground Eagle Cam

Wildlife NewsIntallation Progress:

Installation of the above-ground eagle cams on the Chehalis Estuary will be delayed until after the Fraser Valley Bald Eagle Festival due to continued high water levels.
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Oil Spill ~ Robson Bight

Planet Earth

Environmental groups have cancelled plans to self fiance the underwater investigation of the oil spill in Robson Bight.On Aug. 20 a barge filled with logging equipment spilled 19,000 litres of mostly diesel fuel into this ecological reserve near Telegraph Cove.

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HANCOCK FORUM NEWSLETTER - Issue No 5 ~ November 07 , 2007

NewslettersHANCOCK FORUM NEWSLETTER

Issue No 5 ~ November 07 , 2007
Editors: Cobbler39/Blue Heaven
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image... FEATURE STORY


DO EAGLES HAVE TONSILS? .....AND OTHER QUESTIONS

You may remember Wendy asking several times, "Do eagles have tonsils?" (She knew the answer.)

Tonsils are organs of the lymphatic system and act as part of the immune system to help protect against infection. Our tonsils can be seen on either side of the throat when we open wide and say "Ahhh" ~
like Skye did on June 10th ...image

The eagles 'opened wide' numerous times this past season but we couldn't see if they had tonsils there!

imageimageimage
Mom, April 28, 2007....... Baby Skye in May ....... Skye, June 10,2007

We asked our resource people; AJL, whose expertise and helpfulness is well-known on the forum, and Carla Lenihan, Wildlife Biologist and Executive Director at Hancock Wildlife Foundation. They replied that eagles do not have tonsils in the same way that we, or other mammals do, in our throats. Tonsils are basically lymphatic tissue and because the eagle eats carrion, its digestive tract is lined with plenty of lymphatic tissue to prevent infection.

We sent the question to David Hancock who forwarded it to Dr. David M. Bird at McGill University. Dr. Bird wrote back that, while birds do not have tonsils like we do, they do have cecal tonsils which are found in their ceca which are dead-ending structures coming off the small intestine at the junction of the large intestine. They produce antibodies and play some sort of sentinel role for the lymphoid system.

So..... do eagles have tonsils?

Eagle feet, eagle claws, or eagle talons?

An eagle's feet are very unique. We watched with amusement when Skye stretched a foot that seemed too big for her in front of the close-up camera; we saw Mom's huge feet and talons leave the nest above the tiny, bobbing head of the eaglet; and we saw Skye's talons develop into the powerful weapons they would one day become.

imageimageimage

Animals also have feet with claws, including tiny birds. But the eagle's claws are extremely strong and sharp because birds of prey also use their feet for killing. They need those two-inch long razor sharp claws to grasp a slippery strong fish with scales.

Many other animals have sharp claws, so why do we call the eagle's claws talons? The difference is that an eagle's feet are designed to carry things. The foot has four toes, strong enough to hold up to four pounds when flying through the air. Three toes point forward and one backwards. The bottoms of their feet are covered with rough, scaly knobs called "spicules" that give them a better grip. The powerful muscles and tendons hold the feet firmly shut when carrying heavy prey or perching on a branch.

It is amazing that the eagle can control those enormous and lethal feet when landing on the nest, when delicately straddling incubating eggs, and so carefully avoiding stepping on a tiny eaglet.
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Hancock Forum Newsletter - Issue No 4 ~ October 24, 2007

NewslettersHANCOCK FORUM NEWSLETTER

Issue No 4 ~ October 24, 2007
Editors: Cobbler39/Blue Heaven
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image... FEATURE STORY

EAGLE MIGRATION

The only thing we know for sure about the migration of southern British Columbia Bald Eagles is that they go somewhere for a few weeks every year. The nesting areas are vacated sometime after the young have fledged in August. Because the eagles in this area have not been in the endangered category (protected, yes), funding has not been provided to do costly telemetry studies of the eagle population in B.C. Birds have been banded, but the low incidence of banded birds and reports has resulted in small amounts of scattered information.

After fledging, the young are still dependent on the adults to feed them for a period of up to a couple of months until they gain the experience and skills to find and catch their own food.

The eagles of northern Vancouver Island and further up the coast leave a bit later than the southern Vancouver Island and Fraser Valley eagles but, one thing is certain: the migration includes adults, newly fledged eaglets, and any other non-breeding eagles.

Tracking Bald Eagles

Since 2004, Destination Eagle in the province of Ontario has tracked the journeys of 13 eaglets. These eaglets have traveled extensively but the majority of their time has been spent in the lower Great Lakes basin where they originated. These young birds spend a lot of time in contaminated “hotspots” and suffer a high mortality rate.

The United States has done more extensive telemetry studies of eagle migrations. The birds are fitted with tiny backpacks that hold a lightweight satellite transmitter that beeps every 10 days. In this way, the travels of each bird can be mapped.

The Santa Cruz Predatory Bird Research Group (SCPBRG) at UC Santa Cruz is tracking juvenile bald eagles as they make fast migrations covering thousands of kilometers. The first bird tracked flew some 900 miles in August from its nest at Lake Shasta, in northern California, to the vicinity of the Dean River in central British Columbia. The journey took less than three weeks.

So far, the juveniles they have followed have traveled thousands of kilometers from their birthplaces in California to British Columbia and one to the Great Slave Lake area.

The young eagles forage for dead salmon and learn to hunt for live prey in the late summer and fall. The SCPBRG says these stunning first journeys from the nest are honed by thousands of years of instinct. It is a remarkable coming-of-age quest for food and independence.

Studies of migration routes by tagging wintering bald eagles over several years in cooperation with the California Department of Parks and Recreation at Millerton Lake near Fresno, CA, have shown that virtually all of these eagles migrate to a relatively consistent area within Canada's Northwest Territories, northern Alberta, and Saskatchewan for the summer.

The map below shows a journey which is similar to many others in the study with an adult female traveling north to her breeding ground at Great Slave Lake in the Northwest Territories. The eagles' return journeys are along much the same routes as the northward ones.

image...Backpack image
photo: Journey North 2000

Satellite monitoring of adult eagles in the Skagit River area in Washington State shows a different picture. Their findings document a spring migration (16 February to 5 April, n = 25 movements), and fall migration (8 August and 14 December, n = 5 movements) with the eagles migrating along the coastal corridor from Washington to southeast Alaska, and through interior British Columbia along the Fraser River. Of 20 telemetered eagles, 40% originated from British Columbia, 35% from Alaska, 20% from the Northwest Territories, and 5% from the Yukon Territory.

Radio-telemetry studies of a few Bald Eagles reared in Oklahoma show that they migrate north during the hottest months of the summer to cooler climates such as the Great Lakes area or Canada.

Not all eagles migrate. No one knows how newly fledged eagles know where to go or if some just wander. They usually leave before their parents. It is believed that these are innate (inborn) behaviours. Not all fledglings return to their birthplace.

Eagles ride the thermals (columns of rising air) to high altitudes, then fly long distances at speeds up to 50kph (30mph), soaring on the wind currents until they catch the next thermal and gain altitude again. There can be streams of eagles in the sky, with the birds spread out for many miles.

Where do the eagles of British Columbia go?

This map shows that Bald Eagles are year-round residents of Vancouver Island, the B.C. coast, and southern Alaska.

image

However, it doesn’t explain where the adult eagles of the Saanich and Hornby Island nests go between fledging and fall nest-building. They don't leave in August to go to the salmon runs because they are back at their nests before the salmon spawn.

The Stanley Park Ecology Society is monitoring 17 nests in Vancouver, B.C. They say that many adults and juveniles move to nearby rivers (and their fish runs) as a stable food source.

Gradually, adult eagles are spotted again towards the end of September. The adults return to nesting areas around the beginning of October, plus or minus one week, to reclaim their nest territory. Mid-October to mid-November is nest-building time. They bring large branches to place around the outside of the nest and smaller branches and material for the inside.

The immature eagles straggle back a bit later. This is winter survival time. Colder weather and shorter days are occupied with getting food. Nest-building stops. They depend mostly on fish during this time but also prey on winter-weakened birds. The Bald Eagles gather at the many streams and river estuaries to feast during the annual salmon spawning in fall and winter.

Conclusion

The only time of year that Bald Eagles are absent from Pacific Northwest areas is August/September. I would like to think that the juveniles have set off on the first great adventure of their lives and that the parents take a well-deserved flying holiday (remember Mom's tattered and weary appearance after Sidney finally fledged). They ride the thermals and touch down to forage for food until instinct tells them it is time to join their partners back at the nest and meet up at the rivers for a salmon feast.
Blue Heaven

read on for the rest of the newsletter...
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