Snow Goose x Ross's Goose

Snow Goose x Ross's Goose hybrids (adult and two immatures), Barr Lake, Adams County (Colorado, USA), 10th March 2013 - copyright Steve Mlodinow

(photo ID: 1197)

Snow Goose x Ross's Goose hybrids occur relatively frequently in North America, where their identification can be troublesome due to variation within either parent species. This flock of six hybrids shown here are remarkable: their finder, Steve Mlodinow, takes up the story:

"A six-pack of apparent Ross's Geese was a nice little surprise at Barr Lake, Adams County, CO on 10 March 2013.  I had always thought Ross's Geese were smaller than Richardson's Cackling Geese, so I was somewhat confused, as these 6 small white geese were all about the size of the Richies around them.  Then I realized they all had grin patches and all lacked the grayish patch near the base of the bill.  So they weren't Ross's Geese.  The grin patch, however, was too narrow for Snow Goose, and besides, the birds were small with somewhat delicate rounded heads.  Hybrids!  A six-pack consisting entirely of hybrids Snow x Ross's Geese!  The variability in bill shape was fascinating, with oneimmature rather long billed and some of the adults relatively stubby billed. One immature had rather limited white, approaching the patternof an immature Ross's Goose, the other had gray markings that wereintermediate between Ross's and Snow, even in March (when immature SnowGeese are starting to get whiter)."

Snow Goose x Ross's Goose hybrids (with Richardson's Cackling Geese), Barr Lake, Adams County (Colorado, USA), 10th March 2013 - copyright Steve Mlodinow

(photo ID: 1198)

On the next bird, Steve points out the curve of feathers along the base of the bill, much like a Snow Goose.  The bill size and shape is intermediate, a bit more Ross's like in this bird.  The grin patch is obvious, but not as big as that of a Snow Goose.  Head shape is intermediate.

Snow Goose x Ross's Goose hybrid, Barr Lake, Adams County (Colorado, USA), 10th March 2013 - copyright Steve Mlodinow

(photo ID: 1196)

The bird below is a bit longer billed, but not nearly as thick billed as a Snow Goose.  The grin patch, again, is too narrow for Snow Goose, and the head rather rounded.

Snow Goose x Ross's Goose hybrid, Barr Lake, Adams County (Colorado, USA), 10th March 2013 - copyright Steve Mlodinow

(photo ID: 1200)

Snow Goose x Ross's Goose hybrids (adult and immature), Barr Lake, Adams County (Colorado, USA), 10th March 2013 - copyright Steve Mlodinow

(photo ID: 1199)

In the next photo showing the birds in flight with mainly Richardson's Cackling Geese gives an idea of size comparison, but note that the hybrids are nearer than the Cackling Geese.  Steve points out how white the wings are on the lead immature compared with the one behind it.  The lead bird is intermediate and the rear bird more Snow Goose like.

Snow Goose x Ross's Goose hybrids (with mainly Richardson's Cackling Geese), Barr Lake, Adams County (Colorado, USA), 10th March 2013 - copyright Steve Mlodinow

(photo ID: 1201)

Of the next two birds, seen at different location the following winter, Steve writes that their size and rounded heads induced thoughts of Ross's Goose but the bill was disproportionately hefty, giving that "chimera look" which he says is often seen in this hybrid.  The bird shown below is larger than the nearby Richardson's Cackling Goose, while a pure Ross's should be smaller.

Snow Goose x Ross's Goose hybrids (with Richardson's Cackling Geese and Lesser Canada Geese), Stewarts' Pond near La Salle, Weld County (Colorado, USA), 13th November 2013 - copyright Steve Mlodinow

(photo IDs: 1140-1141)

Steve suggests the next bird may not be a first-generation hybrid. It differs from pure Ross's Goose in having a longer bill without a straight interface between the bill and feathering.  In the first photo it is the tall bird standing behind a Ross's Goose in the centre and in the second photo it's facing right with its neck hidden behind the tall-standing Snow Goose in the middle.

Snow Goose x Ross's Goose hybrid (with Ross's Geese and Snow Goose), State Wildlife Area near Las Animas Fish Hatchery, Bent County (Colorado, USA), 1st April 2015 - copyright Steve Mlodinow

(photo IDs: 2235-2236)

The next is an old photo without data for where or when it was taken, but appears to show two hybrids.  The front bird is more straightforward but the rear bird is more Ross's-like and caused one commentator to question whether it wasn't just a Ross's Goose.  Steve has pointed out that it shows a substantial black grin patch.  There is a suggestion that those Ross's Geese that show a slight grin patch, probably never as large as this, are mainly adults (unlike these).

Snow Goose x Ross's Goose hybrids, location unknown (possibly California, USA), date unknown - copyright Steve Mlodinow

(photo ID: 2412)

The next bird is interesting, being a blue morph.  Steve points out that the blue morph of this hybrid has a blackish colour unlike the greyer hues of a blue morph Snow Goose. It has been suggested that the very rare blue morph of Ross's Goose arose from hybridisation with blue Snow Goose.

Snow Goose x Ross's Goose hybrid, Denver (Colorado, USA), late December 2016 - copyright Diane Roberts

(photo IDs: 3026-3027)

Snow Goose Anser caerulescens or Chen caerulescens

Ross's Goose Anser rossii or Chen rossii