Temperature Makes a Difference

30 December 2023

Over the past week my husband and I traveled to Virginia to visit family, the same trip we made a year ago just as a massive cold front swept across the eastern US. Last year temperatures dipped to 13 degrees F in Virginia. This year the weather was mild in the upper 40s to low 60s. The temperature made a difference in how many birds I saw on the trip. Believe it or not there were fewer birds in mild weather!

For instance, on both trips I visited Back Bay National Wildlife Refuge. In 2022 it was well below freezing yet I saw 29 species including thousands of waterfowl: Canada geese, 250-300 tundra swans, gadwall, wigeons, black ducks, ring-necked ducks, scaup, ruddy ducks, and coots (see checklist here).

This year I saw only 18 species and the water birds were reduced to literally a handful each of Canada geese (heard), tundra swans (heard), gadwall and pied-billed grebes (checklist here). Meanwhile the most abundant species was 40-50+ yellow-rumped warblers feasting on myrtle berries.

This year’s El Niño is has certainly affected the birds. On the East Coast it is warm enough that many don’t have to come south to find food.

Will temperature make a difference during today’s Pittsburgh Christmas Bird Count? I suspect precipitation will have a larger affect. There’s a 90% chance of snow showers and then rain.