Carolina Wren
Carolina Wren
<
2
3
4
5
>
On December 15, eight teams of volunteer birders and several home feeder watchers conducted the annual Thomaston-Rockland Christmas Bird Count. Started nationally in 1900 as an alternative to the then-traditional “side hunts” of wild birds and animals, this annual bird count now extends throughout the Americas between December 14 and January 5 each year. It is the longest-running citizen science database in the world. The Thomaston-Rockland edition began back in 1971.

This year’s tally of 68 species was considerably lower than last year’s record-setting 83 species and the overall numbers were down by roughly a thousand. Many variables are involved in determining the final tallies of bird counts. These include weather and travel conditions on count day, the amount of snow cover and whether fresh water bodies are open or frozen. Food availability (natural sources and at feeders) is always a chief factor. Although many well-stocked feeding stations were observed, bird activity was limited in many instances. Did this mean that, with bare ground conditions, birds were feeding in the local woods and fields? Or were there simply fewer birds lingering at the midcoast?  With freshwater lakes solidly frozen, waterfowl numbers and diversity were reduced proportionally.

While these counts are just a snapshot of the birds inside a prescribed 15-mile circle on a given day, their cumulative scientific value highlights continent-wide shifts in population and distribution of certain species across regions. One noticeable trend is the progressive northward expansion of species in response to generally milder and shorter winters. Red-bellied Woodpeckers, for example, now nest and winter in Maine – six were found on count day. Cardinals (49 this year), Mourning Doves (205), Northern Mockingbirds and Carolina Wrens have become relative newcomers to New England in the recent decades. We continue to note increases in Mallard Duck populations (558) and decreases of Black Ducks (65) as hybridization between the two species favors the former.

Perhaps this year’s biggest surprise was a virtual absence of the irruptive winter finches we had anticipated. No Cross-bills, Siskins, Purple Finches or Redpolls. Waxwings also went unrecorded this time. One saving grace was a cluster of four Pine Grosbeaks at Clark Island. Blue Jay numbers were down (56 individuals), but portions of jay populations are known to vacate the region in years with poor acorn crops. It is no secret that Wild Turkeys are doing well, however. They were re-established in Maine in the 1970s, and now woodlands, commercial gardens (and select bird feeders of lucky homeowners) contain the foraging flocks.  As is often the case, a few Great Blue Herons and Belted Kingfishers manage to hang on during the early winter.

A single Northern Shrike seen at Tenants Harbor was a welcome addition to the count. With a thick hook-tipped bill and distinctive dark facial mask, these robin-sized predators pursue small birds and mammals in winter. Their habit of suspending prey items on thorn bushes and barbed wire fencing has gained them the moniker of “butcher bird.”

After count tallies are entered into the massive CBC database in coming weeks, we will learn where all of those birds we missed on count day were really located. It will be an interesting lesson.