During a couple days midweek last week, Tue, Feb 7 through Thu, Feb 9, I heard SCJU singing around our backyard. That was the first time that I have heard juncos sing this season. Normally, I hear the first junco song around our home a little later in February.
The wintering juncos will sing their dull, muffled, rattling trill in the late winter and early spring, until they move on. I normally sing the last juncos in our yard, during the April 20-25 period. I've always wondered if those last juncos were ones that wintered in our neighborhood, or if those were birds that wintered further south and had stopped by our yard on their way north.
I'm guessing the latter. It's possible that our wintering juncos leave in March. This is where banding birds, during the winter would help to answer this question. Turnover may occur earlier than expected. If I see 20 to 40 juncos in our backyard in mid to late March, are those the same juncos that existed in December and January?
Backyard junco numbers decrease noticeably by late March or early April. The numbers continue to decrease through April, until I no longer see one.
When I worked at the Black Swamp Bird Observatory (BSBO) from late May 2008 to early November 2012, researcher Mark Shieldcastle banded the birds around the BSBO feeders during some winters. Maybe not every winter. He would start banding maybe in late November, but definitely in December, and he would band into March, I think. Since the wintering bird feeder birds had little turnover, he setup the nets only once a week or so. Maybe twice. I don't remember.
In December and January, dozens of American Tree Sparrows (ATSP) would forage around feeders at two locations, along the west side of the small BSBO building. Numbers would total 60-plus. As the winter wore on and Mark banded more, I could see the small, silver, lightweight metal band on the legs of most of the ATSP.
In early February of 2010, I think, we experienced a warm-up with temps in the 50s and big southwest winds. The wind busted up the ice on Lake Erie, stranding a lot of ice fisherman on a large ice flow. During the few days of mild weather around the end of the first week of that February, the ATSP were practically non-existent at the feeders. It seemed that maybe they were enjoying the thaw of snow and ice and were feeding in other areas.
The mild weather ended, and it was back to normal, winter cold. The ATSP returned to the feeders by the dozens as before, except most or all of the ATSP did not have the band. When Mark banded again, nearly all of the ATSP were new birds. Few if any of the ATSP were recaps, the wintering birds.
Turnover among the ATSP occurred in around the first or second week of February. If simply viewing the birds at the feeders, it would have been easy to assume that the same birds were still hanging around because of the numbers. But winter banding proved that the ATSP had made a late winter migration movement, probably a small movement, based upon local weather.
The ATSP nest further north than the SCJU. The last ATSP are usually observed at the beginning of April. Most migrate through in March, but Mark's winter banding indicates that many ATSP probably migrate through the Toledo area in February too.
Anyway, does something similar occur with the juncos in our yard. How long do the wintering juncos remain around our home?
Back to other birdsong this month, o Sat, Feb 11, 2017, I heard an NOCA sing in the morning over our backyard. That was the first cardinal song that I have heard this year around our home. Also singing that morning: WBNU, ETTI, BCCH. But those three sang in January too.
For the WBNU, the "song" is a fast, wavering up-and-down, nasally sound.
American Ornithologists' Union Bird Banding Abbreviations:
- SCJU = Slate-colored Junco
- ATSP = American Tree Sparrow
- NOCA = Northern Cardinal
- WBNU = White-breasted Nuthatch
- ETTI = Eastern Tufted Titmouse
- BCCH = Black-capped Chickadee