|
March 29, 2007  Fly By Me Once… Phil, from Williams Lake, gathers bird sightings from all over the Cariboo then emails the sightings to all the contributors on his list. This week he surprised me with his latest spring bird collection. Many of the avians on his list are early arrivers such as… The American Kestrel, Yellow-rumped Warbler, Sandhill Crane, Northern Harrier, Spotted Towhee, and White Pelican. There was even a Tree Swallow sighting but that elicited more pity for the poor bird than jubilation at the return of the Swallows. …but all this leaves me scratching my head and wondering how I was so caught off guard by these harbinger-of-spring species' The birds somehow managed to slip by me in 100 Mile House, and reappear 50 miles further north in Williams Lake. Rather than be driven mad by my apparent lack of vigilance, I took to the local meadows and stream-sides with a vengeance trying to scare up some of my own sightings. I discovered a Western meadowlark, a Ring-billed Gull, Northern Pintail, a Mountain Bluebird, and two Trumpeter Swans on my outing, but all these birds were also on the “north of 100 Mile” sighting list. Obviously, I could not admit to being less than diligent in my bird-spotting. So, much as a physicist might propose a missing mass theory for the universe, I would need to propose a missing bird theory for my part of the Cariboo. The glimmerings of a theory took shape on March 23rd after sighting a Spotted Towhee in the yard (and hearing of two sightings in other yards around the same time.) Towhees are not unheard of at this time in early spring. It is only later on when they become scarce. (In fact Towhees will not be found around 100 Mile House during nesting season at all. If you really want to see one at that time you must drive straight west for about 40 miles and look for them along the dry Fraser benchlands.) From the Towhees early-in-the-year appearances and later-in-the-year scarcity, I deduced that the Towhee species will brave blustery March weather and a 3000 foot climb in order to cross a plateau and reach their destination. Obviously this wasn’t a bird species to shun my part of the world in March, but was it possible that some bird species were' Could it be that the birds which slipped by me were avoiding the climb and the blustery weather' Was this possible' My theory needed further work… …to the south and west of the plateau where 100 Mile House is situated, there is a stretch of dry country much lower than our plateau. The Thompson River flows along the south side of the plateau, and the Fraser River flows along the west side of the plateau. The rain shadow effect of the Coast Mountain range and its much lower elevation means that the area is drier and considerably warmer earlier in the year. It is a warm, low pathway leading to the interior of the province. A pathway coincidentally which skirts the very place where I keep watch. Isn’t it logical that birds seeking to conserve energy during spring migration would know of and use this corridor rather than ascend 3000 extra feet to a plateau where the lakes are frozen and precipitation falls as snow rather than as rain' Perhaps all the birds seen north of us early in spring, the ones I missed, are the birds using the softer migration route. It all makes sense. Thus vindicated, I march out to the land. Content for today that the birds I saw were truly hardy migrants. In Centennial Park I watched a pair of Common Mergansers and my first pair (for the year) of Barrow’s Goldeneye. I also saw a Dipper, a pair of Hooded Mergansers, a lone male Pintail and a Common Goldeneye. These species, I admit, are not the stuff of impressively early migrant lists but I congratulate them for their appearance. They are the high plateau migrants! Oh, we’ll get our Harriers and our yellow-rumped Warblers in time but ours will be a later, hardier stock. Not for them the banana belt migration where the only dangers are stepping on a prickly cactus or heat dehydration. Welcome back all you tough little buggers! To e-mail Tom CLICK HERE To look at previous column CLICK HERE |
