Bicknell’s Thrush (from allaboutbirds.org)

This morning Roger Pasquier heard the song of a Bicknell’s Thrush at Evodia (the Ramble bird feeder area). He later told Anthony Collerton about it and pointed out the bird, a warm-toned thrush associating closely with a grayer Gray-cheeked Thrush. Collerton issued a Manhattan Bird Alert (follow @BirdCentralPark on Twitter) to let everyone know. He himself had not heard the bird sing.

I arrived at Evodia some minutes later, after Collerton had left, and quickly found a pair of thrushes on the east side of Evodia that matched the stated description. I announced my find to other birders nearby just as the bird was flying to the west side of Evodia.

As I have written before, visual identification is not sufficient to claim a Bicknell’s Thrush, as Gray-cheeked can look much the same. One needs to hear the Bicknell’s song, which ends with a thin, rising pitch.

Both thrushes were staying silent and had wandered out of view. When we started playing the Bicknell’s song on a mobile phone, one of the thrushes came back into view and perched overhead, calling “whee-er”. Soon it flew down and sang. We had our Bicknell’s!

Shortly thereafter I called it in again for Anders Peltomaa and Al “Big Year” Levantin and elicited singing in response. Same later for Joseph DiCostanzo and his American Museum of Natural History walk.

I also heard the Bicknell’s Thrush sing on its own, unprompted, just east of the Gill Source at 10:18 a.m.

A half-hour later Robert DeCandido came by Evodia and helped members of his birding walk see and hear a singing Bicknell’s Thrush.

American Bird Conservancy President Mike Parr and his group were nearby at the time and might have heard the Bicknell’s song. To be sure, I used my phone to call it back again and everyone got close views of the calling and singing  bird.

Bicknell’s Thrush remains a rarity not just in Central Park but throughout its tight migration range along the East Coast. Since identification requires hearing its song, it is possible to get it only during spring migration. Even then, the time window seems to be narrow — I have never had Bicknell’s on more than one day in any May, and there are usually at most only a few days in any May when I hear much thrush song in Central Park. The possible date range for it here seems to be May 12 to May 25, judging by historical Central Park records and my own experience.