Marbled Murrelet

Today's Animal of the Day is making a strong bid for Animal of the Year. Incidentally, it also serves as a reminder that reading Science magazine can be incredibly worthwhile. While perusing a recent issue, I stumbled across an article describing an effort to measure the age distribution of the marbled murrelet.

(This is an excerpt from the Science article, found here)

Managing Murrelets

One challenge in conservation management is estimating what a sustainable population should look like. Geographic and genetic information can readily be obtained from museum specimens, but if, as for many birds, there are morphologically distinguishable age classes, then age-ratio analysis can also provide baseline rates for reproduction and survival. The output of such an analysis can be used to set targets for population recovery. Beissinger and Peery have championed the case of the marbled murrelet (Brachyramphus marmoratus), an endangered seabird from the Californian coast which unexpectedly nests high up in old-growth coniferous trees and whose plight has only recently come to attention. The murrelet population is being decimated as a result of attacks from crows, by logging, and especially via the loss of the fish that they eat. Reproduction is expensive for murrelets; they lay a single egg that weighs up to a quarter of the adult bird's weight, and adults will abandon breeding in the face of insufficient food. There are some methodological risks with age-ratio analysis, but for this bird, contemporary data from field studies were compared with the museum data, which showed that the reproductive success of contemporary murrelets is almost an order of magnitude less than it was a century ago.

Reactions:
1) Have you EVER heard of a better name than the MARBLED !@^&ING MURRELET? That is a rhetorical question.
2) It's an interesting story. No one knew they nested in trees until someone found one of their nests. In a tree. That's pretty rudimentary science, there. I need to emphasize, it is extremely surprising that this seabird nests in a tree. It would be like a penguin nesting in a tree.
3) The part about the downward forces on their population is especially sad, I think-- I mean, habitat loss and a decimation of their food source, those both suck. But imagine losing your house, losing your food, and then being ATTACKED BY CROWS! The worst.
4) George's stream-of-consciousness: "I must see a picture I must I must I must"

Read the wikipedia article, please and thank you.


And then! AND THEN! The chicks have a face only a mother could love:
Okay, I might love that face.

Until next time,
George

Beaver

Today's Animal of the Day is one of the true keystone species of the world. This term is bandied about pretty frequently, but shouldn't be--- a keystone species is not just a species that is "important" and deserves to be protected. Rather, a keystone species is one that has a disproportionate effect on its environment. In any given ecosystem, the removal or addition of certain species will have a much greater effect overall than the removal or addition of others. It is along these lines that we come to understand that the beaver is one of the most disproportionately influential species on Earth. This should be understood on both ends: the removal of beavers from locations where they were previously found has a large effect, and the introduction of beavers into water systems where they previously weren't found also has a large effect.

The reason beavers are so influential is because of their status as ecosystem engineers. As you might imagine, the physical characteristics and realities of the waterways in an ecosystem have a huge impact on the composition, distribution, and population sizes as well as interactions of the species in the system. Thus, when beavers change the flow and level of rivers and streams by building dams, they have a direct impact on a huge number of species around them.

You might be thinking that a beaver would have to build a really big dam to have such a big effect. The biggest dam ever discovered was 2,140 feet long, 14 feet high, and 23 feet thick at the base.

There has been a lot of interesting research about the stimuli that cause beavers to have the impulse to build dams. For instance, beavers will pile branches next to a loudspeaker if it is making sounds like a running river!

Sorry it's been so long. It's going to be a busy couple of weeks. I hope to keep the blog going, but probably will just have links instead of longer, textual entries.

Cheers,
George