Eagles in Homer, Alaska

[mark_chappell]

Bill: VERY off topic, but your concern is well founded. There was a fairly recent and

somewhat controversial paper in <I>Nature</i> <A HREF="http://

news.nationalgeographic.com/news/

2003/05/0515_030515_fishdecline.html">summarized here</a> showing information to

the effect that 90% or so of large pelagic predators (tuna, billfish, seabass, etc.) are gone.

The species are still around and sometimes remain reasonably abundant, but average

sizes are small and the substantial number of really big specimens that are in the

historical fisheries records are now extremely rare.<P>

 

Not sure if you can access this but the original Nature paper is <A HREF="http://

www.nature.com/nature/journal/v423/n6937/abs/nature01610.html">here</a> --

Myers and Worm, <i>Nature </i>423, 280-283, Rapid worldwide depletion of predatory

fish communities.

[bill_thorlin]

Mark - thank you for the information - I almost wish you hadn't.

 

A sad parallel with elephants - no big tuskers left and not likely that there will be any more with the gene pool gone.

 

I fear we are destroying this planet at an ever increasing rate.

[mark_chappell]

<I>A sad parallel with elephants - no big tuskers left and not likely that there will be any

more with the gene pool gone.</i><P>

 

The problem with pelagic predators is likely not genetic -- it's just that these fish are

under such high harvesting pressure that they are caught before they get old enough to

become really large. As far as elephants go: I'm not aware of any data that there's a

genetic issue. I'd bet that, like game fish, if indidual males survive long enough, they

(and their tusks) will get big. My population geneticist friends tell me that you have to get

to <B>REALLY</b> low population size before there's much impact on the gene pool --

like, on the order of 10-20 individuals or less. African elephant populations never got

<B>that</b> low, did they? Here in California, northern elephant seals went through a

much narrower bottleneck than 'land' elephants -- by some estimates there may have

been much less than ~50 animals (and only a few breeding males) around 1900. Today

there are 150,000 + elephant seals and they are sill expanding -- in fact, breeding on

mainland beaches, something they didn't do when the state still had grizzly bears.<P>

 

There was a paper (forget the journal, maybe <I>Science</i> or <i>Nature</i>) within

the last few years that

claimed a genetically mediated reduction in horn size in bighorn sheep on some range in

Canada, due to

artificial selection by hunting -- strong selection against males with big horns. But that's

the only

reasonably well supported example I know of along those lines. I'd guess that if (a huge

'if') there is adequate room for them in Africa, elephants will do fine and eventually there

will be big-tusked males again.

[mark_chappell]

Perhaps setting an off-topic record: reference to <A HREF="http://www.oxfordjournals.org/

our_journals/jhered/freepdf/84-443.pdf ">genetic diversity and population bottlenecks in

northern elephant seals.<a/> Note that population has to get really low before there's

substantial loss of genetic diversity.

[bill_thorlin]

Apologies to Scott for hijacking his thread.

 

Mark - I will have to try and recollect my source for the elephant comment - one point about elephant populations is that they do become disconnected, often because their migration routes are no longer accessible to them. A number of the game parks in East Africa have seen numbers drop alarmingly at times, especially the smaller parks, maybe small enough to cause such a problem.

 

I believe there is also a problem with cheetahs - I have seen something on Photo.net in this regard and will again try and check.

[mark_chappell]

<I>A number of the game parks in East Africa have seen numbers drop alarmingly at

times, especially the smaller parks, maybe small enough to cause such a problem.

</i><P>

 

This (isolated populations) is certainly a hot issue in conservation biology, but population

geneticists and evolutionary biologists will tell you that it takes very few immigrants to

maintain a reasonable level of genetic diversity.<P>

 

<I>I believe there is also a problem with cheetahs - I have seen something on Photo.net in

this regard and will again try and check.</i><P>

 

The cheetah is a famous case study of apparently low genetic diversity due to a

hypothetical population bottleneck (a period of very, very low population size). Here's <A

HREF="http://www.pnas.org/cgi/content/abstract/90/8/3172">one paper</a> on this

topic (there are quite a few more). But there is strong argument about whether recent

cheetah population declines are largely due to "inbreeding" effects or to ecological factors

(crowding, habitat loss, etc.). And at least one study shows that while cheetahs may have

low genetic diversity, other large carnivores are not that different and some have lower

diversity than cheetahs. Certainly the northern elephant seal shows that a species can

have explosive population growth after a very severe population bottleneck.

[heatherforcier]

<p>As to the temperatures in Homer, be prepared! I have visited in February twice. Layers are best - my hands got the most cold of anything. Good cold weather attire can be expensive but worth it.</p>

 

<p>As to sunshine, I don't think I saw but five minutes of it in a week and a half in February 2004. But this past February 2005, the first five or six days were straight sunshine. Makes it a little difficult to expose those birds right - bright overcast tends to work pretty well although the sky looks more drab. And clear skies mean colder temperatures. But, the sun can be fun for photos, plus you get some great shutter speeds for flight.</p>

 

<p><center><img src="http://www.hforcier.com/postings/BaldEagle0875_HFORCIER.jpg">

</a></p>

 

<p><img src="http://www.hforcier.com/postings/BaldEagle0142_HFORCIER.jpg">

</a></center></p>

[bill_thorlin]

Mark - I have not been able to locate the reference for the elephant comment - I suspect it was from East Africa. Basically what I am driving at is the fact that the last big tusker in East Africa that I am aware of ( named Ahmed, location Marsabit and protected by Presidential decree ) died in the early 1970s and as I said he was the last, the others all went some time before. Over 30 years have now elapsed and the elephant population has decreased significantly since then. The signs do not appear good.

 

The cheetah reference was in relation to the population in Namibia where I understand they are trying to introduce new breeding stock to alleviate the problem.

[mark_chappell]

Bill: I know about Ahmed, but wasn't he supposed to have been 60-70 years old (or more)

when he died? There simply may not be very many males that old, if most of the tusk-

bearing elephants were killed during the years of extreme poaching. I'm certainly not

claiming

that elephants are doing well, and in fact their future looks pretty grim (too many people, not

enough land). All I'm saying is that there's probably no genetic reason for their decline, and

if enough animals are allowed to get to a natural old age, some of the males will generate the

huge tusks we're familiar with from old photos. Really monster tuskers were probably

always unusual and rare, even when populations were much larger than at present.

[bill_thorlin]

Mark - when I worked ( and lived ) in Kenya in the 70s two of the audits I was resonsible for were the ( then ) Kenya National Parks and the East African Wildlife Society. Some of the information I had access was then ( and some probably still is ) confidential. Large Tuskers were even then a topic of interest due to their rarity and the reduction of overall numbers.

 

As part of the job I had to visit Tsavo West Park Headquarters and stayed with, the then, Warden Ted Goss. Again the topic came up and he ( if I remember rightly ) said he had never seen a big tusker since he was very young. I also had to check the "ivory store" which contained mostly confiscated poached ivory, some of it having been there for quite some time. I honestly do not recall seeing tusks of any noticeable size.

 

Given the bleak outlook for elephants at the present time I suppose that the captive specimens ( zoos etc. ) may prove to be the only ones that could possibly develop large tusks. I have never seen anything on this but may try to do some research.

 

The age of Ahmed ( his picture is on the lounge wall - sadly not taken by me but by a close friend ) was a matter for speculation and in the end it was felt that he was "mzee sana".

[lancemcvay]

Haines is still a great place for bald eagle photography. It's a 2-hour ferry ride from me and I went up last month, the week before Thanksgiving. I camped in my car, which I don't really recommend, as the second morning I woke up, it was -15F

<p>

The highway to the Canadian border is about 30 miles long, and runs parallel to the Chilkat River. There's a late salmon run there that attracts eagles October - January, with late October and early November being the peak season.

<p>

I wasn't really trying to keep count, but I saw well over 500 eagles. It's estimated that somewhere between four and eight thousand eagles gather there over the course of the winter.

<p>

The highway is plowed, but still fairly slick. If you don't have a vehicle, you'll have a hard time getting out to the birds, unless you go during the <a href="http://baldeaglefestival.org/">Bald Eagle Festival</a>. They run buses out to the various pull-outs. The round-trip ferry ride with a vehicle under 15ft in length is about $100, so you could fly into Juneau and rent a car there if you were so inclined.

<p>

Here are a couple shots that I got while I was there.

<p>

<a href="http://sacredartichoke.com/coppermine/albums/11-14-2005%20haines/IMG_2535.jpg">eagle1</a>

<p>

<a href="http://sacredartichoke.com/coppermine/albums/11-14-2005%20haines/IMG_2530.jpg">eagle2</a>