Well Tweets, I got five private responses to this so we will, for now,
forge ahead.

I've found a couple of Black Swift experts who believe that the
proximity to evaporating water is important for nice mud to hold the
nest together, but the majority opinion, like tweeter Judy Meredith
suggested, is that the evaporating water provides a cooling,
moderating temperature for the developing young. When mom and dad are
gone all day, and maybe more than a day, the chick is able to slow his
body way down to conserve energy. The official name for this process
is torpor. While swifts may look like swallows, they
share the taxonomic order Apodiformes with the Hummingbirds, who are
torpor masters.

Here is a great reading article on the topic titled "Eats like
Godzilla, Sleeps Like the Mummy!", from a UW Biology Department
Newsletter.
http://research.amnh.org/users/nyneve/hummingbirds.html

I also got a response from Brian Adamowski LaComa that shows a whole
brain load of original thinking that's worth sharing with you.

"Perhaps the humidity breeds gnats and?midge insects that the birds can
then feed on themselves?? Perhaps the moisture keeps parasite
populations down someway?? Is there some sort of refraction in the
light that keeps predators from recognizing easy, abandoned prey?? How
about it just keeps them cooler?"

We had a couple of posts a while back about swallow nest abandonment
because of bug infestations. The Black Swifts reuse the same nest year
after year. Hummm???

I will leave you with a pretty picture. The California State Waterfall
Champ for the most nesting Black Swifts (20 pair), McArthur-Burney
Falls. This is worth the look.
http://puremass.com/philliao/photo/1998/jpg/burney1.html

Larry Schwitters
Issaquah


On Wednesday, August 24, 2005, at 04:37 PM, Larry Schwitters wrote:

> Tweeters,
>
> I realize that this is a very different kind of post and apologize in
> advance if it's inappropriate.
>
> I would like to attempt to foster so thoughtful cyberspace
> conversation. Some of you already know all of this, but for others it
> should be all new.
>
> The Black Swift is one of North America's most poorly understood
> birds, and what is known is a work in progress. Where these birds
> build their nests is a lot of the problem. Danny Tyson found a Black
> Swift nest near Mission, BC and writes about his discovery and the
> birds nesting needs in a Spring 2004 Discovery Magazine Article.
>
> "The nests are notoriously difficult to locate since the swifts have a
> unique breeding ecology. All Black Swift nest sites must meet certain
> specifications (Knorr, 1961). These include the presence of water, a
> high location, inaccessibility to predators, unobstructed flyways to
> and from the nest, and a situation protected from direct sunlight.
> Thus, the nest sites are located on steep, sea-sprayed cliffs, in sea
> caves, or at inland canyons near waterfalls. To make them a little
> harder to find, the birds only return to these sites near nightfall to
> feed the young."
>
> It's beginning to look like the high location and unobstructed flyways
> are perhaps not a must, and the lone baby swift can tolerate a bit of
> sunlight, but what does seem to be vital is evaporating water very
> close to the nest.
>
> Why is this so?
>
> No need to raise your hand. Just use your keyboard.
>
> Larry Schwitters
> Issaquah
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