Wednesday, June 29, 2016

GREEDY GREBES GRABBING GRUB


I have been following the Pied-billed Grebes at Magnuson Park in Seattle for about two months now, and they never fail to be interesting and always offer good photo ops. Various members of the family often rest among the lily pads; presumably they are expending most of their energy digesting a good meal.

The adults continue to feed their young Oriental weatherfish (Misgurnus anguillicaudatus), a loach from Asia that has invaded the pond from Lake Washington, where it was unintentionally introduced. We have now found four species of fish in the pond, including Prickly Sculpin (Cottus asper), Pumpkinseed (Lepomis gibbosus) and Largemouth Bass (Micropterus salmoides). The first is a native species, the other two introduced long ago throughout the region for sport fishing. I still don't have any idea how they got into the pond.


Anyway, there must be a lot more loaches, or they are easier to capture, as again and again that's what I see the adult grebe feeding to the young. In this case, one young got the fish and another followed it around and around for a while. It was obvious the lucky young was trying to swallow it but was having a hard time because it couldn't slow down. But finally it managed to gulp it down.





The adults feed to the young anything than can catch, here a dragonfly, an adult male Common Green Darner (Anax junius) that perhaps was captured when it was mated with an egg-laying female at the water surface. I doubt if a grebe could pluck one out of the air.

Another one is about to swallow the larva of a California Spreadwing (Archilestes californicus), a large damselfly that is common in the pond.


There are no more ducklings for the male grebe to savage, and it seems to be getting along with the single American Coot that now lives in the pond. Maybe this is the stage in nesting when that fierce aggression is relaxed. But I've seen the male chase its own young violently on several occasions in exactly the same way, rushing it from underwater, not sure what that is all about. I still haven't been able to get a photo of it, as it happens very quickly and only once. Maybe it's just "I've had enough of all that begging."


Grebes swim amazingly rapidly underwater, and here you can see the size of the foot that, together with its mate on the other side, propels them like that. The long toes are lobed rather than webbed as they are in a duck, and both adaptations seem to work equally well.

Dennis Paulson

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