The Snow Goose need not bathe to make itself white. Neither need you do anything but be yourself.
On one of my first Christmas Bird Counts over 25 years ago, at what was then Pungo National Wildlife Refuge (now the expanded Pocosin Lakes NWR), I ran into a well-known birder who was scoping a huge flock of Snow Geese. He asked if I had seen the Ross’s Geese mixed in with the thousands of Snow Geese. I had heard of Ross’s Geese, but never seen one. The flock suddenly erupted, and as the mass of birds circled us, he exclaimed, “There…there they are, three of them”.
I looked, but really couldn’t see a different bird in the flapping sea of white and black wings. That was my introduction to the subtleties of goose identification. Together, Snow Geese and Ross’s Geese are often referred to as light geese. Light goose populations are increasing nationwide and Snow Geese are now believed to be one of the most abundant waterfowl in the continental U.S. My recent trip to Bosque del Apache in New Mexico provided great opportunities for observation and comparison. In NC, if you see even a single Ross’s Goose mixed with thousands of Snow Geese, it is a good day (most Ross’s Geese overwinter in California and other western states). At Bosque, the Ross’s Geese are much more common, with small flocks easily spotted along the edges of the large flocks of Snow Geese.
Snow Geese are dimorphic, meaning they occur in two color morphs – one light, and one dark. Until 1973, the two were considered separate species. The field guide I learned to bird with listed the dark-morph as the Blue Goose. The dark-morph is estimated to make up less than 5% of the Snow Goose population that winters here in NC.
Adult light-morphs are white with black primaries, which appear as black wing tips when seen from below.
Adult dark-morph Snow Geese have dark gray-brown bodies with white heads and upper necks. A range of intermediate color forms occurs between the light and dark morphs.
Immature birds of both morphs are grayer overall.
Both color morphs have a distinctive black “grin patch”, or “lip line” on their bills. They also have pink legs and feet.
An adult Ross’s Goose looks like a miniature Snow Goose (a little more than half the size of an adult Snow Goose). Other distinguishing features to separate them from Snow Geese are the lack of the prominent black “lip line” on the shorter, stubbier bill, and a more rounded head. They also have a grayish/bluish base on their upper mandible with caruncles (warty bumps) developing with age. The back edge of the bill-feather line on a Ross’s Goose is straight, whereas that on a Snow Goose, is curved. They also have a more rapid wing beat and a higher pitched call than Snow Geese. Dark-morphs are rare in Ross’s Geese. Immature Ross’s Geese are grayish. Hybrids do occur, with the best distinguishing features being an intermediate size, bill length, and a slight curvature to the back of the bill line.
The comparison is best seen when the two species are next to one another. They are also easy to tell apart if they occur in the same line of a flying group of light geese, with the noticeable size difference being easy to spot with practice.
On the last afternoon, a drive along the south loop at Bosque put me in close proximity to several hundred light geese lounging, bathing, and conversing. The birds settled into a routine and, for about an hour, a small group of us sat and watched as the geese went about their business.
Many of the birds rested, head tucked into their back feathers. They seemed to keep tabs on me with one open eye even as they “slept”. Interestingly, several of the napping birds would slowly rotate in a tight circle, perhaps as a way to survey the scene as they rested.
When not resting, the birds in this flock were preening, stretching, bathing, and discussing unknown subjects with their neighbors. Several bathing styles were evident varying between awkward splashing to vigorous head dipping. One additional method was new to me – the bathing flip. It involves a head dunk that turns into a complete body flip in the water accompanied by some vigorous splashing. The short video below includes a few examples (see if you can distinguish the Snow Geese from the Ross’s Geese swimming about)…
Often, the bathing sequence concludes with a prominent wing flap where the bird rises up on the water surface and flaps its wings a couple of times before settling back down to resume preening or simply rest.
More geese joined our group from time to time in flocks varying in size from a five or ten to larger flocks of fifty or more. And, since it was a small pond, we observers all had front row seats to some beautiful landings.
After about an hour, something changed and the flock’s behavior and calling became more fidgety.
Soon, a few birds took off – at first groups of ten to twenty, then a few more, until, finally, about half the remaining flock lifted off and flew directly over our heads. That was followed shortly by the lift-off of the remaining geese and the once noisy pond was empty. Most of the birds flew out into an adjoining cornfield and started to feed. Less than an hour later, most will have flown off to their evening roost in some shallow water found throughout this section of the refuge, safe from most predators.
Such is the daily routine of the light goose brigade: rise before sun up and dazzle the onlookers; move out to another shallow roosting spot for perhaps an hour, then gradually fly off to fields for awhile; fly back to a pond, then back to a field, and so on, until late in the day when they return to roost together in huge flocks to squabble and jostle the night away; start the whole thing all over again the next morning. I marvel at how these birds manage their energy budget since they never seem to truly rest (perhaps at night?) and are always on edge, waiting for some unseen cue to send them skyward.
But having spent some quality time with them, I now have a better appreciation of their beauty, and of how to more easily distinguish between the species. Raucous or not, they are still magical to see and hear as they fill the sky at Bosque or here at home in North Carolina.