Monday, December 17, 2012

Trivia Question of the Week

This week's trivia question is appropriately related to eagle migration: How far do bald eagles migrate?

Hint #1: It's not nearly as far as an arctic tern

Hint #2: We've determined these distances through the use of leg bands and telemetry.

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Thursday, December 13, 2012

Eagle Update!

Although 4N's tag is out of commission, we still have four birds to follow! We're always excited to see where these eagles are moving, and we hope you are, too.

First up, the females! Both females, 3E, the adult, and 4P, the immature eagle, have been sticking around the Chilkat Valley.

3E has made a couple trips to the ridgeline south of the Chilkat, but is otherwise hanging out around the area between 19- and 21-mile on the Haines Highway-- pretty much the only region of the Chilkat River that is unfrozen this time of year:


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Monday, December 10, 2012

4N

Rigby and I are back in Santa Cruz, adjusting to things we haven't seen in a while-- stoplights, traffic, and sunshine, just to name a few. We've finally managed to get internet up and running in our new place, so it's back to blogging!

Today's entry focuses on one of the more frustrating aspects of working with wild animals: data loss. So far, we've been getting pretty reliable information from the GPS tags on our eagles, but the data are not without problems. Since the tags are solar powered, they need to have reliable sunshine to keep the battery charged and the device functioning. In southeast Alaska, where snow is a daily occurrence and daylight hours are rapidly diminishing, it's tough for the tags to get the juice they need. This is complicated by the fact that the Chilkat River is surrounded on both sides by relatively steep mountain ranges. Even when the sun does come out, much of the river is still in shadow.

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Monday, November 19, 2012

Trivia Question of the Week

Last week, when we posted about the capture and processing of bald eagles, we mentioned that, up until five years of age, eagle molting patterns can be used to determine how old a bird is. Past five years of age, when eagles reach adulthood and take on the characteristic appearance of their species, with a white head and tail, it's impossible to tell how old they are. So, how long do bald eagles live?

Hint #1: The fact that eagles don't mature until five years of age suggests that they're fairly long-lived-- animals that live shorter lives mature earlier.

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Wednesday, November 14, 2012

Meet the eagles!

Get ready to meet our eagles! We captured five eagles on the Chilkat River this year, and we'll be tracking their movements from now until the transmitters fail (or fall off, or the eagle... dare I say it?... dies)(Which is not going to happen. I hope.). If all goes as planned, we'll see the daily movement patterns of these eagles for at least the next three years! We can't wait to see where they spend their time during different parts of the year.

We captured our first eagle late morning on Saturday, November 3rd, using the ballistic net. A sick juvenile eagle couldn't resist the free food in front of our net launcher, and began to feed. An adult eagle came and roused the juvenile off the bait, and fed in its place. The result? We netted our first bird, a healthy, hefty adult female!

4N, just after being freed from the net

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Monday, November 12, 2012

To Catch a Predator (Part 2)

Our snares are set, our net is at the ready, and we've been standing around in the snow since dawn, waiting for the eagles to come in. We keep a close eye on our snares and bait with binoculars and spotting scopes.


Each time an eagle nears a perch we've erected, or flies over the bait in front of our net launcher, we hold our breaths. Typically, the eagle moves on, or perches nearby. We sigh, and wait for the next close encounter.

Then, unexpectedly, an eagle flies down and lands next to the chum carcass set out in front of our ballistic net. It looks around, cautiously, before beginning to feed. We wait until the eagle has its head down, focused on tearing a nice, juicy bit of chum off the carcass, and then-- "Fire!" We trigger the ballistic net remotely, and the .22 gauge blanks power three padded projectiles, launching the net from its housing out and over the bird.

"We got it!"

Everything is a rush. We sprint from the roadside, where we've been watching, down the river embankment to our freshly-netted eagle. We must move quickly, to ensure that the eagle doesn't escape from the net, or get too tangled. Immediately, we secure the talons of the eagle in our hands, and place a hood over its eyes. Eagles receive most of their sensory information visually, so when they can see what we're doing, they get stressed. With the hood on, however, they immediately calm down, and are relatively docile in the hand. Unlike many mammals, birds do not need to be anesthetized during handling. The hood keeps the eagles calm enough.

We then begin the process of extracting the eagle from the net. Here, Steve Lewis and Dr. Scott Ford work the netting off the eagle's wings.

Steve and Scott work the netting off the eagle
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Wednesday, October 24, 2012

More Trail Camera Photos!

This latest series of trail camera photos comes to you courtesy of the Herman Creek Chum salmon run. Coho and Chum are pretty much the only salmon running this time of year. Coho are a little harder to come by, so anything that's eating salmon is probably going to be eating Chum.

Like these bears:


Or these. How many bears do you see in this photo?


Did you count four? There are the two obvious ones, then part of a third on the right edge of the frame, and part of a sneaky fourth behind the branches along the left edge of the frame.

Here is a less sneaky adult eagle:


and some mergansers and a raven at that same site:


We had a couple coyotes in this set. Here's one of them:


Eagle party! More eagles have been arriving every day. There is a citizen science group in Haines that does weekly eagle counts. Last weekend the tally was 775. It won't be too much longer before there are thousands.


Take a look at this handsome youngster:


We also have some ravens fighting over scraps.


Another photo of a wolf!


And our first moose photo! Well, sort of, anyway.


This last one is tricky. Along the bottom part of the frame in the middle, there is another "first" camera sighting. A rodent! It's impossible to identify the species, or get much beyond "rodent-like small animal." But there it is! Maybe not quite as grand as the brown bears, wolves, and eagles, but I think it's fun to see them just the same.



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Saturday, August 25, 2012

Trivia Question of the Week

Alright, time for the trivia question of the week! This week's question:

What is the largest bird in the United States?

Hint #1: The species neared extinction in the 1970s

Hint #2: The decline was likely caused by a combination of factors: habitat loss, poisoning, and lead ingestion

Hint #3: They have a wingspan of over 10 feet, can weigh up to 30 pounds, and can live up to 60 years in the wild

Hint #4: They are scavengers

Hint #5: They live in California

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If you guessed California Condor (Gymnogyps californianus), you're correct! California Condor once ranged over the entire western United States, but today they're one of the most endangered species in the world, and their habitat is limited to parts of California and Arizona. Just over 100 birds live in the wild, and most of these were captive-bred animals that are still very closely monitored and regularly fed. The photo above is an image of a California Condor in Grand Canyon National Park.

So, was that a trick question? ;)

The Bald Eagle (Haliaeetus leucocephalus) is no lightweight either-- it's the largest raptor (bird of prey) in the United States. With a wingspan between 6 and 8 feet in length and weights ranging between 7 and 14 pounds, Bald Eagles may not be as large or hefty as California Condors, but they are definitely big birds. Just check out the size of their tracks!





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