Saturday, June 25, 2011

Ugly Ducklings

It's molting season again! Yes, it's that time of year when most of our local birds go through their annual complete molt - as anyone who has been on one of my recent walks will know!  One way that this annual molt is obvious to us locally is the shear volume of dropped flight feathers from ducks, geese and swans in Bunker Pond - a veritable tideline! The reason why we see this is because these waterfowl have a short, sharp shock strategy when it comes to molting. These birds drop all their flight feathers in one go, which means they are effectively flightless for a short period. This is a risky strategy, but it means that they can go through the molt relatively quickly and soon be back on the wing and ready to head south for the winter (since most of our waterfowl breed at northern latitudes and migrate south in fall). To help protect against being caught by a predator, these birds will flock up as there is safety in numbers (if a predator gets a meal, chances are it won't be you!) and they will also tend to move to traditional molting areas that have been used for many generations.

First signs of molt - eight Mute Swan primaries, all shed in a single wing flapping session on Lake Lily!

Mallards (and other ducks) have a main molt now too and it is at this time that the males go into what we call their 'eclipse' plumage. This sees the normally rather colorful males adopting the drab colors of females which perhaps makes them less obvious to predators during a time when they are more vulnerable to attack. It may also mean that the birds can flock up to molt together without getting too stressed at being that close to another male! So if you're at the South Cape May Meadows any time soon, don't be surprised if you don't see any apparent male Mallards. The thing to do is to check the bills; females have brown and orange bills, males have a bill which is greenish yellow (brighter when breeding) and looks like an unripe banana.

Another group of birds showing rather severe molt processes at the moment are the larger gulls, and boy do they look a mess. Indeed, I reckon they're so ugly at the moment that no-one is interested in photographing them. I spent some time last night trawling the internet for photographs of young gulls taken in late June or early July and I really couldn't find any! With a late run of horseshoe crabs along the beaches at the moment, I went out to look at some local gulls and found - well, a mess! Here's a few of them:

Here's what I would consider to be a pretty 'average' American Herring Gull, for its age and time of year. This is what you can either refer to as a first-summer, or second-calendar-year bird. In other words, it was hatched last year. I've desperately tried to use other molt or plumage terminology such as cycles or words such as basic or alternate but find them totally non-intuitive and of no use when trying to get people off the starting blocks with understanding the subject. The problem in trying to define a first-summer plumage for these gulls, however, is that they don't really have one! During their first 12 months or so after losing juvenile plumage,  some species of larger gulls are pretty much continually molting from first-winter to second winter, gradually replacing the full suite of feathers.

Here's a bird that is a little more blotchy and darker than the bird above, but still fairly typical of what you see here; again, it's an American Herring Gull and shows a classic half pink, half black bill and a lot of dark body blotching. They also tend to be rather dark at the back end with dark bands wider than pale bands on the upper and under tail feathers. It might be easy to mistake this for a Lesser Black-backed Gull, based on the darkness of the upperpart feathers, but that species is much paler on the under and upper tail feathers as well as on the body feathers in general, while the bill is usually all dark at this age.

Now here is an ugly gull - I'm sorry, no offence intended, but it is pretty bad! Birds like this are pretty common here too and can be rather confusing as they're not in the field guides! This too is an American Herring Gull, though most of it looks pretty pale. This is most likely due to the bird having wintered well south of here - perhaps in Florida - where the sun really bleaches out the feathers and breaks then down. Thus, all the pale feathers are old ones, whilst the dark blotches are new feathers coming through. This bird struck me as surprisingly heavy-billed, giving it a Great Black-backed Gull look, but I think this may be due to a thinning of the head feathers which actually makes the head look smaller relative to the beak.

Here's the same, heavy-billed American Herring Gull as above in a more convincing pose, showing the dark tail and relatively dark rump. Look at how the outer primaries have been reduced almost to just the central shafts which must make flying much harder! New, grayer, inner primaries are coming through, while some of the wing coverts are completely missing, leaving a strange white patch in the middle of the wing.

For reference, here's a typical second-summer (third-calendar year) American Herring Gull. By this age, the adult back color is apparent and can safely be used to help identify the species. Look just how worn those old wing coverts are now though! Notice too that the bill is now largely yellow, though still with much black towards the tip.

Also for reference, here's a typical first-summer Great Black-backed Gull. Note how the upperparts are much more strongly checkered in appearance, while the feathers under the tail show more pale than dark.

Sightings update: Both the Eurasian Collared Dove and the Purple Gallinule remain at Cape May Point and up to six Lesser Black-backed Gulls are being reported variously along South Cape May Beach. Small numbers of Glossy Ibises are feeding in pools which are drying out and getting ready for returning shorebirds...

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