Tuesday, February 23, 2016

Cackling Goose Conundrum

Where do I start with this post? Let's see, I have written in the past about finding Cackling Geese at several locations in the NYC Metro and Long Island areas. In one such post, I included several tips on how to identify Cackling Goose in the field--in our case, this was related to the expected subspecies b. Hutchinsii Hutchinsii. The post (see here) was not very technical but I did provide some starting points that any birder with a critical eye and patience to sift through flocks of "White-cheeked Geese" would find useful. Additionally, I also included a link to David Sibley's online series (a work in progress) that is an excellent starting point in distinguishing Cackling from larger "White-cheeked Geese."

Is the 3rd bird from the right a Cackling Goose? What about the 8th Goose from the right?
A recent "White-cheeked Goose" (see link to photos here) in Central Park NYC which was first identified as a Cackling Goose then as a possible Lesser Canada Goose has stirred up a useful discussion. For some, it was a bit amusing while others like myself, took it quite seriously. Some have mused that the fuss about the Central Park Goose, is much ado about nothing. Apparently, birders on Long Island and other parts of New York deal with these types of larger than average "Cackling Types" every season during Geese migration. Contextually, that may be true but the discussion opened up a very interesting debate on what do with the odd "White-cheeked Goose" that shows up whose features does not fit the conventional wisdom (ID features from literature by Bird Experts) that birders have relied on since the AOU split in distinguishing Cackling Goose from other "White-cheeked Geese." While much has been written on how to identify and separate the Cackling Geese subspecies, almost one feature has been consistent in the literature and is considered a primary indicator. It is HEAD and BILL shape. Size and plumage are considered to be secondary indicators by birders and researchers.

Classic looking Cackling Goose (b.h. hutchinsii) in Queens NYC
The Central Park Goose to many, including those considered "Geese Experts" did not not pass the expected Richardson's Cackling Goose ID features and so began the debate on what it was? I myself took the position that it was not a Cackling Goose based on my experience of observing Cackling Geese in the field and speculated that it was one of those "Lesser Canada Type" things (for lack of a better term) or a Runt Branta Canadensis. The question on identification was posed on ID Frontiers (a listserve for BIRD identification discussions) and it set off a discussion that was quite educational. When Geese researcher, Ken Abrahams, responded that he thought that the Central Park Goose was a very difficult ID and conservatively called it a "Hutchinsii Variant" I was not surprised at all. I have often suspected that we probably had larger than the expected b. Hutchinsii Hutchinsii slip past us but wondered at the use of "variant." It seemed to me a term used for lack of knowing what the Central Park Goose really was--still, it was interesting to have a researcher confirming that on the breeding grounds, larger Cackling Geese have been observed. What bothers me though, is the lack of evidence in the form of photographs. I have crawled the web for such examples and I have yet to see these larger than average Cackling Geese clearly identified in any photos with supporting literature. Perhaps, someone will set me straight after reading this post and point me to resources.

A very pale breasted Goose. B.c. Canadensis or something else??
Additionally, out of the discussion was the premise that there was no chance of "Lesser Canada" (B.c. parvipes) occurring in our area. I had long decided, based on records and range, a Lesser Canada would be quite rare in our area; however, I was still intrigued that some commentators were taking the position that the chances of seeing B.c.parvipes in our area was almost zero percent. To make matters even murkier, the discussion got into whether there was any difference in Taverner's vs Lesser Canada. Hello...say what!?!  That bit, was even more astounding with several researchers weighing in having different opinions! It seems from this discussion that there is a need for a re-write on the subspecies of Cackling Geese. The thread on ID Frontiers has hit a lull but could get active again; at the moment the consensus is that the Central Park bird is NOT a Cackling Goose. With species overlap, environmental changes and an obvious learning curve with the "White-cheeked Geese" complex, we are sure to have this discussion again. My advise to birders who encounter Geese like this would be to document it but don't get hung up on affixing a label.

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