Sunday, January 29, 2012

Snowy Job

So tons of Snowy Owls are descending on northern American states:

Bird enthusiasts are reporting rising numbers of snowy owls from the Arctic winging into the lower 48 states this winter in a mass southern migration that a leading owl researcher called "unbelievable."

Fascinating. So I read on to be enlightened about "the most significant wildlife event in decades," and I discover:

An especially plentiful supply of lemmings last season likely led to a population boom among owls that resulted in each breeding pair hatching as many as seven offspring. That compares to a typical clutch size of no more than two, Holt said.

Since lemmings are 90% of the snowy owl's diet in breeding season, lots of lemmings led to a population boom of snowy owls. That's why they are heading south in unprecedented numbers. That is interesting. So how do we know there is a population boom?

I read on and discover:

He said snowy owl populations are believed to be in an overall decline, possibly because a changing climate has lessened the abundance of vegetation like grasses that lemmings rely on.

Oh. We now learn that the snowy owl population is in decline. And this is because the supply of food for lemmings--which snowy owls rely on--has declined. Which must mean there are fewer lemmings.

So snowy owls are flocking south because of a population boom but the population is in decline?

And the snowy owls had a population boom because they had lots of lemmings to feast on but a "changing climate" has reduced the food supply of lemmings--presumably meaning there are fewer lemmings for the snowy owls to feast on?

Huh. How did the reporter become so wise in the ways of science reporting?

Well, there is a reason this is so confusing:

This winter's snowy owl outbreak, with multiple sightings as far south as Oklahoma, remains largely a mystery of nature.

"There's a lot of speculation. As far as hard evidence, we really don't know," Holt said.

Ah, they really don't know. But whether there are more or fewer snowy owls or lemmings--or whether someone turned them into newts (before they got better)--we can at least speculate that "changing climate" is at fault. We can at least settle lemming-like on that explanation, right?

Now let's get a big grant to settle the question by seeing if we can build a bridge out of snowy owls.