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HANCOCK FORUM NEWSLETTER - Issue No 7 ~ January 23, 2008

Newsletters
HANCOCK FORUM NEWSLETTER

Issue No 7 ~ January 23, 2008
Editor: Blue Heaven


image... LETTER FROM THE EDITOR

This Issue of the Hancock Forum Newsletter is less than usual due to my preoccupation with another matter. However, I am publishing it while the content is current.

Blue Heaven

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NEST NEWS
Sidney Nest
  • Snow on the nest in early December...janner
    imageDec2image
  • Adult eagle flies past the nest, December 15, 2007...jkr
    image3:08pm
  • Surprise visit at dusk, 4:50pm on December 22, 2007...queenie
    imageimageimage
  • Another flyby on January 8, 2008...SharonFeeney
    image
  • Skipper captured Dad visiting the nest at 3:44pm on January 9th .....VIDEO: Eagle Visits the Nest (3:23)
    He plucked every tall stem off the weed in the nest bowl so we aren't likely to see the expected yellow flowers bloom.
    imageBH
    Later that afternoon, SharonFeeney captured an unusual approach to the attic branch:
    image4:36pmimage

__________ Read on for more...
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HANCOCK FORUM NEWSLETTER Issue No 6 ~ December 01, 2007

NewslettersHANCOCK FORUM NEWSLETTER

Issue No 6 ~ December 01, 2007
Editors: Cobbler39/Blue Heaven
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image... FEATURE STORY


FOOD HABITS OF THE BALD EAGLE

The Bald Eagle’s food habits are some of the most versatile of any bird in North America. Their diet consists of a very broad range of animal matter. The mainstay of their diet is a variety of fish, which was previously underestimated because studies of nest site debris did not account for the fact that fish remains decompose readily and that fish bones are digested by Bald Eagles and may not appear in castings (regurgitated pellets).

The Bald Eagle is an environment helper by eating a variety of marine life and other animals as well as carrion of all types. The three main food types are: fish, aquatic birds, and carrion. Depending on what is available, they will shift quickly from one food to another. In this way, the eagle is able to return to its nest territory each year because the variety of prey it obtains prevents over hunting of the area.

Beebe (l974), sums up the remarkable versatility of this species: "To a singular degree the Bald Eagle emulates the behaviour and hunting techniques of every other kind of raptorial bird on the continent, but it has also developed a trick or two of its own. Bald Eagles are variously scavengers, carrion feeders, pirates, fishermen, mammal or bird predators, and they capture the latter either from the air, on the ground, or from the water.”

The high productivity of young in the nests in the Strait of Georgia has been linked to the abundance of prey and rich variety of food the region supplies; fish, marine invertebrates (crab and shellfish), seabirds and waterfowl, as well as a regular fare of prey obtained from foraging on farmlands. They have been observed feeding on stillborn lambs in the spring.

On Southeast Vancouver Island and the Gulf Islands, the location of the Saanich and Hornby nests, Vermeer et al. l989 reported: "Frequency of prey remains beneath nests was 52% birds (mostly Glaucous winged Gulls), 34% fish (mostly Ling Cod and rockfish), 12% marine invertebrates (mostly crabs and clams), and 2% mammals (mostly carrion). Glaucous-winged Gulls were by far the most frequent species of prey. Up to 50 eagles attracted to hake brought to surface by upwelling in Active Pass." These findings are consistent with fish remains being much less persistent or obvious than are remains of birds and mammals.

Bald Eagles invariably choose fish, when available, over other food types. In many areas, 90% or more of the Bald Eagle's annual diet is composed of fish. Seasonal sources of food are:
  • (January to April) - schools of herring
  • (March – April ) – eulachon runs
  • (May – June) – hake brought to the surface at tidal rapids
  • (late August through January) – spawning salmon
  • Birds - nesting season near seabird colonies and wintering waterfowl on delta regions
  • Intertidal invertebrates, such as crab and shellfish

Being opportunists, Bald Eagles take advantage of fishing scraps and bycatch along the coast. They are not shy about alighting on fishing boats to look for free offerings:

image ... imagephotos: Blue Heaven

Eagles do not chew their food. They use their beaks to rip pieces off and tear it into smaller portions. They will swallow a small animal whole. The food passes into the crop, a swelling at the base of the esophagus. Food can be stored in the crop, allowing the Bald Eagle to quickly consume large amounts of food for later digestion. In this way, they can avoid having to share their catch with others. After gorging themselves, the bulging crop is noticeable.

image ssportrait: Blue Heaven
Victoria and Sidney, May 24, 2006

The birds swallow indigestible items such as fur, bones, fish scales, claws, beaks and feathers, as well as other things that could damage or block the bird’s digestive tract. These are formed into a compact pellet. The soft meat is separated and digested in the stomach. They make themselves throw up these pellets, usually right before they eat their next meal. This is called 'casting a pellet'. The tightly packed pellets found underneath nest trees can be pulled apart and examined to provide information about the Bald Eagle's diet. (Click on pictures to see videos):

VIDEO: Ejecting A Pellet, March 3, 2007 (2:30)
(Sidney Nest, poor quality recording of the Flash Cam - Mom on nest watches Dad, then copies him)
image VIDEO: Malkin Eagles, July, 2007 (3:39) ...image
The Stanley Park eagles were seen trying to regurgitate pellets this past summer up on their treetop; Dad getting rid of a pellet - you can see it drop. .....Other Wildlife/Eagles/Stanley Park Eagles
...Blue Heaven

read on for more...
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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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HANCOCK FORUM NEWSLETTER Issue No 3 ~ October, 2007

NewslettersHANCOCK FORUM NEWSLETTER

Issue No 3 ~ October, 2007
Editors: Cobbler39/Blue Heaven
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image... FEATURE STORY


image The Chehalis River Estuary

The salmon are heading up the Chehalis River to spawn!

Go to the Cameras page at the Hancock Wildlife Channel to watch the salmon swimming up the spawning channel. The link to click on is under the picture of a rosy red salmon: .....Hancock Wildlife Channel/Underwater View at Chehalis Fish Hatchery

imageimageimage

This is just like having a real live aquarium on your computer monitor, complete with live sound from a microphone hanging over a water cascade close to the camera. At times, peoples voices can be heard near the microphone, muffled by the pleasant bubbling sound of the water.

After a lot of rain, the water can become murky, but usually clears up in an hour or two. HWF is temporarily sharing bandwidth with the Fisheries Office so transmission can be a bit intermittent.

There is a constant procession of salmon of all sizes and colours swimming past the camera, mostly Coho, Sockeye (red) and a few late Spring salmon, as well as the occasional trout. Sometimes those big snouts get right up to the camera. This means that the eagles are not far behind! ...and bears! ...and, well, you know, ...Bigfoot! - because this is Sasquatch country. (To date, there is no evidence that Bigfoot follows the salmon spawning, but why wouldn't he?)

Bigfoot items for sale to raise funds for the Hancock Wildlife Foundation, such as this
Bigfoot Watches Over The Eagles mug imageBH (back of mug)
which can be found at .....HancockWildlifeFoundation/CafePress/Bigfoot Items

There will be two estuary webcams coming soon. They will be installed out on the estuary when the Harrison River and surrounding waters have receded. We will be able to watch the eagles and other wildlife feeding on the spawning salmon. In the past, more than 1000 eagles have been seen in this area on a single day.

The Fraser Valley Bald Eagle Festival will be held on November 17th & 18th, 2007, at an area known as the Tapedira Estates, just to the west of the estuary. David Hancock and Richard Pitt will be there as well as other familiar HWF members who are able to attend.

The 10th Anniversary of the Fraser River Bald Eagle Festival in 2005 was celebrated by the release of a young rehabilitated eagle. See Richard Pitt's story and pictures of this event here: .....Hancock Wildlife Channel/Wildlife News/Tenth Anniversary Celebrated by Eagle Release.

image image
photos: Richard Pitt

During the Festival this year, they will be featuring video taken by hand-held cameras in and around the Tapedira Estates area and are hoping to include interviews and commentaries by local naturalists and conservationists.

image Salmon spawning, Tapedira
photo: Richard Pitt

A VIDEO by Keta is ready for viewing at YouTube .....Installing The Underwater Cam At The Chehalis Fish Hatchery (9:54)
(There are other videos on the same YouTube page showing different aspects of the Chehalis River.)

The Cast of Characters as submitted by Richard:
David Hancock - the reason we all got so wet in the rain
Bob Chappell - creator of the cameras
Richard Pitt - shouting and pointing
Karen Bills - keeper of loose wires from underfoot
and of course Keta - playing herself

Everyone appears to be having great fun in the rain, lowering the webcam with ropes into the channel. The camera is attached to a cement block. David hams it up with what he calls "the fish microphone", making sounds like a gurgling fish!

Go to the Hancock Discussion Forum to see members' comments, screenshots and videos .....Hancock Live WebCams/The Chehalis River Estuary/Discussion and Screenshots & Videos where this VIDEO by beans will have you humming all day .....They Swam & They Swam

The Underwater Cam is now LIVE so you can see what the eagles are anticipating for breakfast, lunch, and dinner!
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