Saturday, September 11, 2010

Seal Pup

The edge of Puget Sound is a mere 700 feet from my front door as the Northwestern crow flies.  On quiet mornings or evenings I can smell the salt air.  I usually take a walk the beach with my dog Ranger about every weekend, unless the tide leaves little beach exposed.

Sometimes I will see a seal slowly raise its head just above the water maybe 50 or so yards out.  They watch me as I walk the beach then slowly dunk down again.

At this time of the year, the mother Harbor seals have given birth.  They will leave their newborn pups on the beach while they go off and forage.  It is very important to understand that the pup is not abandoned and is best left alone.  Ranger spotted this one before I did but I was able to call Ranger back before the pup panicked and broke for the water.
















Another sign of fall are the Heerman's gulls having made their annual migration northward from the beaches of Baja California.  They'll head south again before winter's wet and chill hit.  These gulls are all gray with a beautiful red beak. 

Monday, September 6, 2010

Pigeons, Windows, and Ectoparasites

Warning: This post is not for the squeamish. It contains graphic photos of a dead pigeon.

Pigeons or technically Rock Pigeons (Columba livia) are ubiquitous in the urban environment of temperate latitudes. Its natural habitat is open and semi-open environments with cliffs, usually on coasts, in western and southern Europe, North Africa, and into South Asia. The urban environment provides similar cliff-like structural elements on buildings as well as abundant food sources (don’t feed the pigeons). I’m not a big fan of pigeons but I can appreciate their adaptability.

Window strikes kill between 100 million and 1 billion birds in North America each year (David Malakoff, Audubon magazine, March 2004). Because glass is transparent and reflective, the birds see a reflection of the outdoors and try to fly through what looks like unobstructed open space. Like a science fiction force field, they are immediately repelled. We have birds occasionally strike the windows of our home, most recently a Red-breasted Nuthatch (Sitta Canadensis), who did recover but remained dazed on the ground for more than a few minutes. Some birds do not recover and it’s always a sad moment when this happens.

I had some field work last week at a vacant car dealership, the kind of place with large showroom windows and the perfect environment for pigeons. Below the large windows, I noticed a dead pigeon on the ground with a trail of dried blood trickling from its beak.





















It was an obvious window strike. If you look close at the next photo, you can see the faint impression of two bird strikes on the window. The impression shows the body and outstretched wings in flight.
















I took a close-up photo of the pigeon’s head. I could see a few specks but without my geezer glasses they were just specks. When I downloaded the photo, I noticed that some of the specks were actually insects, bird lice.
















The next photo is an extreme enlargement showing one of the lice.
















Pigeons, and probably most wild birds, harbor an attractive mix of ectoparasites. The one in the enlarged photo is likely a slender pigeon louse (Columbicola columbae). The slender pigeon louse belongs to a group of lice known as chewing lice, specifically to the Superfamily Ischnocera, who feed on the downy part of feathers and softer fur. The slender pigeon louse eats the fluffy parts of the pigeon’s feathers. Think about this the next time you’re inclined to feed pigeons.

Friday, September 3, 2010

Relationships

At this time of the year, as summer wanes, the rim of Puget Sound is ringed in bright yellow flowers of Puget Sound gumweed (Grindelia integrafolia). The gumweed seems to thrive in the breezy salt air and sandy soil that fringes the Sound. It is a harbinger of fall and of the dull gray days to come.

The lives of gumweed and a drab grayish brown moth known as the Hooded Mountain Owlet (Cucullia montanae) are intertwined. It was the colorful caterpillar curled inside a flower that caught my eye as I walked the sandy flats at Meadowdale Beach.






















The Hooded Mountain Owlet moth flies in July and August. The caterpillars feed on gumweed then pupate underground. There is only one generation per year.

Puget Sound gumweed ranges from British Columbia to northern California, seldom straying too far from salt water. It is a member of the sunflower family (Asteraceae), whose members include such familiar plants as dandelions and many others.