A tale of two birds — and one ‘city’

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This story starts way back in early April 2012 up in the high basalt rims along the Snake River in northern Walla Walla County.

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Three gray-crowned rosy-finches with two protruding from cliff swallow nests and the third attempting to select its evening roost site.

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A cliff swallow.

There, a rapidly forming colony of round mudball nests takes shape, each with a spout-type entrance hole protruding from the side and dropping down.

Hundreds of cliff swallows pass each other in sweeping waves as they come up from the river’s edge lugging a mouth full of mud to complete their nests a beak full at a time.

The swallows have just arrived from the Central American tropics, where they have spent the previous six southern summer months hawking flying insects out over humid pastures.

Whatever cliff swallows do, it is done en masse, amid a constant din of loud grindings, clickings and chirpings — even with mouths full of mud.

There is nothing so alive as a new colony of them bringing up material for their nests.

The 5.5-inch-long, dark, slate-backed swallows select a site with a slight overhang sometimes hundreds of feet above the ground.

Each beak of wet mud is carefully placed along the developing edge of the new nest, and each nest has a dark wet edge that fades to a pale gray-brown as the mud dries closer to the base plastered to the basalt rim.

On the ground these energetic birds stand on tiny feet with their narrow wings held high over their backs with spastic, pulsating twitches. The rapid wing movements act as an alert, clueing in the rest of the colony into where the best mud is.

It will take upward of  575 mouthfuls to complete a single nest.

Once completed, nests are often plastered right next to each other and often share common walls as well as the ancient magma of the overhanging rim.

Nests often face east or north and are climate controlled by the swallows sticking their heads — dark but with a pale forehead — out the access hole.

Adult females lay four white eggs with brown dots and spots all near one end. By mid-July the young are raised and the whole event is over.

Great flocks of young and adult cliff swallows now wander about this region, foraging out over the rivers and lakes.

By late August these beautiful swallows have started to drift to the south and migration is on.

Their round, mud-daubed nests are now baked hard in the late summer sun. A few wasps, ants, mice and spiders come and go in this silent city high above the dammed river.

Months pass into mid-October. Then a new occupant arrives, this one from the far north and the high Cascade and Rocky mountains.

It is a spectacular bird known as the gray-crowned rosy-finch.

At 6.25 inches long, this dusky, rose-covered creature is here to spend the winter.

They form flocks of more than 300 birds that spend the day out feeding on seeds.

By 3 p.m. they return to the great colony the cliff swallows built, and after much chasing and flying about each finch settles on a mud nest to fly into.

Then, with its head filling the entrance hole, they comment to each passing rosy-finch still out trying to select a nest in which to spend long, cold winter nights.

These well-insulated birds warm up the interior of the weather resistant mud structures as they sleep.

They will winter in this area until mid-March when they head back to the north and the high country where they breed.

What happens after the finches depart?

Spring rains and winds began the process of breaking apart the mud nests.

By April most are shattered or have fallen off the basalt rims leaving, a wide open site for the new colony to be constructed at the arrival of the cliff swallows from Central America.

Such is the dependency between the cliff swallow and the gray-crowned rosy-finch, at least from the finches’ perspective.

So if you spot a colony full of round mud nests, please resist shooting or throwing stones at them.

They are winter homes for one of our most beautiful winter finches.

After all life is good!    

Mike Denny is president of the Blue Mountain chapter of the National Audubon Society. He can be reached at m.denny@charter.net., or by calling 6-8 p.m. weekdays at 529-0080.

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