Sunday, April 14, 2013

Sharpe Park

Today, I visited Skagit County's Sharpe Park for the first time.  I only recently discovered that it was there.  I found a network of old growth forest trails I can spend many hours exploring.  The headlands offer terrific views of the San Juan Islands across Rosario Strait.  I also found a large pond and wetland, tailor-made for wildlife.  The park is located on the west side of Fidalgo Island off Rosario Road.

The pond was my first stop and right off the bat I spotted two handsome male Hooded Mergansers (Lophodytes cuculattus) in the company of a male Ring-necked Duck (Aythaya collaris).  The peaked crown and a more decorated bill distinguish the latter from either the Greater or Lesser Scaup.  I saw no females of either species.

The Hooded Mergansers were eager to display their crests.  This makes me think there were hens somewhere in the area.  Like Wood Ducks, they like to nest in tree cavities near water.  I spotted at least two large nest boxes at the edge of the pond.  These may have been put up for them.  They are year-around residents on Fidalgo Island.

Ring-necked Ducks are less common here, and they do not breed in Western Washington.  Their breeding grounds include river valleys in the Cascade Mountains and Eastern Washington, especially in the Okanagan.  Unlike the Mergansers, Ring-necked Ducks are ground nesters.

We have had a lot of rain over the last few days.  Because of this, I expected to see one of our local mascots, the Banana Slug (Ariolimax columbianus).  Sure enough, this fellow was right on the trail, deep in the woods.  So far, my theory that Fidalgo Island Banana Slugs have no spots is proving to be true.  On Whidbey Island, just across Deception Pass, all the Banana Slugs seem to be spotted.

After exploring some of the trails in the woods, I circled back to the pond again.  This time, I spotted a pair of Mallards (Anas platyrhynchos).  They are probably our most common and familiar ducks locally.  During the winter, gatherings of a thousand or more may be seen in the fields of the Skagit Valley along my commute to work.  They like to nest near water, but it may be up to a mile away.  I suspect this pair will be guiding up to fourteen ducklings around the pond by summer.  Platyrhynchos, incidentally, means flat bill.  With the exception of Muscovy Ducks, all domestic ducks can trace their genetic ancestry to Mallards.

Out in the Cattail beds, Red-winged Blackbirds males were singing to claim their territories.  I could also hear Spotted Towhees and Chickadee-dee-dees.  Pileated Woodpeckers were calling all around me and I found their recent excavation work in a dead snag.  The evidence of new shavings at the base of the trunk gave it away.

I also heard a ratcheting-buzzing call I can't identify.  I have heard that same call in the Skagit River Delta.  Perhaps someone can help me out with that.  It always comes from dense plant growth.  I anticipate I will be making many return visits to Sharpe Park to see what else it has to offer.  Maybe I will finally get that call identified.

Tuesday, April 2, 2013

Tree Swallow

Last week, I was pleased to see the Tree Swallows (Tachycineta bicolor) had returned to my favorite Fir Island nature site.  This is the Spur Dike Trail at Wiley Slough in the Headquarters Unit of the Skagit Wildlife Area.  The dike provides easy, dry ground access deep into the wetlands of the Skagit River delta.  Tree Swallows migrate north from their tropical wintering areas earlier than any other swallow.

The scientific binomial Tachycineta bicolor literally means "fast mover with two colors."  Tree Swallows are indeed fast movers.  They typically feed by catching insects on the fly, soaring and swooping at lightning speed.  Unlike eagles and gulls which like to perch and pose for photos, these swift birds are difficult to catch with a camera.  They might land and perch for only a moment, then dash off on the fly again to the tune of their high-pitched calls.

Fortunately, one bird decided to stop and rest a minute.  Although the lighting was not the best, this gave me a chance to get some photos.

The Skagit delta provides the ideal habitat for Tree Swallows.  They like to nest in open areas near water where there are standing dead trees for nesting according to iBird.

Tree Swallows are cavity nesters.  They use natural crevices and the chambers created by woodpeckers and other borers.  They also readily take to nest boxes provided by humans.  Someone has put up more than 30 nest boxes along the Spur Dike Trail.  A few more have been added this spring.  I presume the Washington Department of Fish and Wildlife who manages the site is responsible for the nest boxes and I appreciate that.

Males arrive at the nesting grounds ahead of the females to establish territories.  While I was watching this fellow, his mate decided to join him.

I found it confusing to read that Tree Swallows were described as both monogamous and polygamous by different sources.  Apparently, they form stable pair bonds, at least for a breeding cycle.  The offspring in a particular nest, however, may have different fathers.  Polyandry is the specific term for this.  The same behavior has been observed in Eastern Bluebirds.  This is a strategy that insures reproductive success and genetic variation within colonies.

A group of Tree Swallows is called a "stand."  With several dozen pairs, the Spur Dike Trail at Wiley Sough is a major stand indeed.

This new sign was recently erected at the dike.  The site is on the Great Washington State Birding Trail.  The sign also reveals it is part of the Greater Skagit/Stillaguamish Delta, a site of regional importance in the Western Hemisphere Shorebird Reserve Network.

You can find the Headquarters Unit at the end of Wiley Road off Fir Island Road in Skagit County, Washington.  If you come up for the tulips this month and want to escape the tulip tourists, this might be a nice side trip.  It would definitely be a respite from the crowds.  Tulip tourists are typically not the nature trail types.  Midweek is the best time.  Don't forget to bring your Washington Discover Pass.