All About Double-crested Cormormants At Union Bay

 Here is a recent post from the Union Bay Watch Blog published by Larry Hubbell, long-time local photographer and birder.

Loch Ness?

Double-crested Cormorant is the only cormorant species in the Northwest often found around freshwater. It is also the only avian species on Union Bay that will sit for long periods with its wings fully extended.

Apparently, they have less preening oil than other aquatic birds, so they must work harder to dry their feathers. On the other hand, their totally soaked feathers may retain less air and enable faster maneuvering underwater, which is a handy skill for a piscivore.

They are also very social and can often be found log-lounging with fairly consistent intervals between them. The spacing is not accidental. 

The bird on the far right with the light neck and chest is immature. It most likely hatched out during the year this December photo was taken.

Here is the same group a few moments earlier. With threats and vocalizations, they worked out the "pecking order" and the distance between perches. It does seem like the more mature birds often prefer the higher and drier positions.

Here is another example that reinforces the idea. The two birds in the most elevated positions have very dark feathers, indicating maturity, while the three younger birds, with lighter-colored neck feathers, have the three lowest positions. 

Cormorants are not always found in groups. Although, if you watch a single bird long enough it will usually return to the collective. They seem to go their separate ways primarily while looking for food. 

Being very efficient hunters apparently enables them to spend a major portion of their  lives sitting in the sun and watching-the-world-go-by. It is not surprising that one name for a flock of cormorants is a sunning.

Notice the wide web feet on short legs which are positioned near the rear of the body. 

Their propulsion system is so efficient that even when they are near the surface they often paddle about with only their head and neck above the water, unlike most aquatic birds. 

I am not sure whether our River Otters (Click Here to see more) or our Double-crested Cormorants are the closest creatures we have to Loch Ness Monsters?

Once captured, a fish can struggle and flip its tail but they are unlikely to escape after a Cormorant closes its serrated bill on their slippery flesh.

A Cormorant's most striking feature is probably its bright green eyes. Cormorants also have one other striking feature, which is often hidden, but still must be included in this discussion.

The expansion of the neck as it swallows the fish is also noteworthy.

In this photo, without a fish, the normal neck size is considerably smaller.

This week while watching Duck Bay, I saw a sudden disturbance break the surface of the water.

I noticed it was a Cormorant with the head of a large fish in its mouth.

The fish was so large I was uncertain whether the Cormorant could lift its own head while holding the fish.

With a smaller fish, a Cormorant will often toss it into the air to position it for a final head-first dive into the belly of the bird. This time the Cormorant twisted and turned in the water for quite some time, without any apparent progress. 

I was starting to suspect that the Cormorant would have to give up and abandon the fish. 

I wonder if overly ambitious Cormorants ever get a fish stuck in their throats? With nature, there is always something to keep us wondering. For example, you may be wondering where are the crests mentioned in the Cormorant's name? 

This is a timely question. The crests generally begin to appear during the breeding season. If you look closely (binoculars are helpful) during March and April, you will probably see that some of our adult cormorants have two black crests similar to the bird in this photo. 

Most are black, however, a few of their crests are white. Apparently, among the Double-crested Cormorants in Alaska, white crests are normal. 

The migration patterns of Double-crested Cormorants are also interesting. They are often year-round residents, along the West Coast, from Alaska to Mexico, and also in Florida. There is another portion of the population that is especially migratory. They nest in central southern Canada and the Dakotas. These birds primarily fly south towards the Gulf Coast in Winter. Click Here to see a dynamic abundance map that displays their annual migrations.

Both adult males and females can have crests in Spring, although among males they are typically larger.

Occasionally they have additional feathers, called plumes, scattered about in other areas of their bodies. These feathers are most obvious when they are white.

Here is an example of an adult with a white crests and an immature bird with no crest at all.

I have not seen Cormorants nesting near Union Bay. However, I have watched them gather nesting material in Spring. 

Maybe the issue is a lack of safe nest sites. I have read that they often nest on islands. However, on Union Bay, all of our year-round islands are close enough to shore that they are easily reached by raccoons. (As demonstrated in the Save Our Swans post).

You may be wondering what happened to the Cormorant with the very large fish.

It turned out it was able to open its expandable mouth and at least partially lift its head while holding the fish. In Birds of the World, I found this reference. (The) "Wide jaw-opening is facilitated by nasal-frontal hinge at junction with cranium." Unfortunately, I have not yet secured a photograph that clearly illustrates this capability.

 

In fact, in this case it appeared like the fish may have bypassed the nasal hinge via the left side of the cormorant's mouth. 

In either case, we can clearly see that the neck is distended to over twice its normal width. The Cormorant apparently knew what size of fish it could handle.

Afterward, it did not even try to fly. It paddled over to the west side of Duck Bay and found a branch sticking out of the water. It carefully climbed up to an elevated perch and began drying its wings. I suspect it sat in the same spot for a very long time while digesting the meal.

Their other striking feature, beside their green eyes, is a bright blue mouth during breeding season. I suspect this is used to attract a mate. I am not certain if this would work for humans but I suspect it might get a lot of attention.