On Rare Birds and Cold Snaps
Fall migration gets birds moving and the late fall, especially into early November, is known as "rarity season". This is a time when many off-track birds are found, and sometimes the weather can help. In this blog post we'll look at how a few groups of rare birds are impacted by cold snaps and snow falls seen during this time of the year.
Granivores at Feeders
It doesn't take much snow to cover seeds that were previously abundant. This drop in natural abundance will make human-offered food like black-oil sunflower and white millet more appealing to birds like finches and sparrows. Birds can sense low pressure systems arriving, and a spike in feeder activity is often noticed before the arrival of a storm, providing a good opportunity to look for unusual birds in close proximity to our homes. The day(s) following new snow fall are often when unusual seed-eaters are found at feeders.
In Maine we've seen an uptick in the Eastern Towhee reports at feeders since the snow dusting that hit last weekend (check any you see for Spotted). New York, New Jersey, and Newfoundland have all had Golden-crowned Sparrows recently so perhaps it is time for one to show up in Maine!
Insectivores and Wastewater
These late fall cold snaps, even without snow, are a death blow to most insects. One place we often see insectivores, especially warblers, lingering into the early winter are near wastewater treatment facilities. These spots usually have open warm water where a few flying insects are able to survive - and warblers seem to be able to find them. Mix wastewater treatment and some half-decent habitat (plus a south-facing hillside) and you've got gems like Saco's "magic hillside".
Frugivores on Suet
This might be a stretch to associate with just temperatures dropping as there is still plenty of fruit around (winterberry and mountain-ash are plentiful most Falls). Many of these fruit-eaters are also insectivores, so the drop in that food causes them to turn to readily available protein sources: suet. Warblers, orioles, and tanagers are especially well known suet-eaters in winter. In addition to putting suet out, fruit (like orange halves) are a great way to attract unusual birds.
Even though winter is well on it's way, there's always reason to be out looking for unusual birds.
By Doug Hitchcox