Moorhens mating

This week the local pair of Moorhens have been mating. Females in Moorhens and Coots, and presumably other rails, have a curious way of inviting their partners to mate: They bury their heads down into their chests.

Pair of Moorhens

There are now two Moorhen pairs in the park. They own each one end of the pond, a pair owns the island and the other the 'rock' with a couple of clumps of marginal plants. Today the island pair was very cosy, both individuals together, the one on the left preening around the neck of its partner. Moorhen males are slightly larger and heavier than females, so the larger individual on the left is likely to be the male. The Coot pair abandoned the park after their two failed breeding attempts on the stolen Moorhen nest.

A coot pair settles

Two of the coots have stayed in the park and today my suspicions that they were a pair were confirmed. They have shown a lot of interest on the nest that the moorhen who nested in the tree has built at the base of the tree on the water, on the free time allowed by the care of its now two chicks. But that will be something for a different post. On the top shot, one of the coots examines the moorhen nest closely.

Shortly after, the Coot was chased away by the Moorhen, the nest owner.

One of the coots calls the other with a trumpet-like call.

This morning, both coots were near each other. One of them picked a piece of stem and carried it to a clump of vehetation on the shore and rearranged it using her feet and bill. Then, the other coot approached and gave it chase closely, with the first coot swimming to the shore, standing and adopting the curious position of a receptive female, head curled down under her chest. The male then clumsily climbed on top, although he fell down before completing the copulation. I get the impression these are first time breeders, and the breeding instinct is just kicking in. The following are a couple of shots of coot mating pairs taken in another local park where coots are plentiful, illustrating the female position. They often mate on or near the nest. When they are on the water, the female actually submerges her head.

Coots settling in the park

I wrote about the visiting coot a few posts ago, but there has been new developments in the local park, a few days ago two coots were present and today I counted three coots. They were quite dispersed in and around the pond, but from a particular location all were visible. If they are just coming in or they have been here all along since I saw the first one, I do not know. They are relatively vocal, appearing to keep in touch with each other. This afternoon, two of them seemed quite content, preening close to each other, while surrounded by playing children and lots of people in the park, they most likely dispersed from another park, where they have grown accustomed to people. Male and female Coots have similar appearance, although males are larger and heavier, so possibly the individual in the foreground on the shot above, much larger, is a male. Male and female, however, have very distinct calls. I hope that at least a pair stays in the park as they will provide opportunities to get to watch them closely and learn more about their behaviour.

One of the coots being chased away by the resident Moorhen (with its nest in the island tree).

Coot about to dive

This is the third coot, note its very large frontal shield, protruding from the top of the head and stained pink. The two individuals at the top of the post have much smaller shields.

Coot diving

We have a visiting Coot in our local park. It is quite used to people and a good photographic subject. Coots dive for a few seconds - they appear to be very buoyant - and lift pieces of vegetation from the bottom, to feed on the surface.

A front view of the coot.

Here is a short video of the coot diving for food.

Coot portrait

This coot called my attention due to the large size of the frontal shield. She came quite close to the shore in a local park and I was able to take her portrait.

Bold as a coot

Coots are the odd ones out in their family. Unlike other rails, they are bold, noisy and aggressive birds. Instead of searching for cover, they are all out, even their nests are usually placed in the open water and they are as prominent that you cannot miss them. Their squabbles amongst themselves and with other birds may carry out through the winter, as some birds keep their territorial behaviour year round. Coots have ashy-black bodies and black heads where a strikingly contrasting white frontal shield and beak is one of their most distinctive features. Unlike the long, thin toes of the Moorhen, coots have lobulated toes with side extensions - similar to a Grebe's - that allow them to dive in search of the algae and underwater plants that form a good portion of their diet.

The Coot "flippers"

But lets go back to the frontal shield. The size of the shield changes through the year depending on the bird reproductive status. Both males and females have frontal shields although the males' are larger, but both change in parallel, getting bigger in size as the start of the reproductive season approaches, and peaking in February -March.

(from Visser 1988)

Birds holding a territory have thicker and larger shields than birds not defending one.  Experiments on the American Coot, a close relative of the Eurasian Coot, showed that frontal shields enlarged when coots were injected with testosterone pellets, while they become smaller when injected with estradiol. At the same time, the birds climbed up in the pecking order when injected with testosterone due to an increasingly "pugnacious attitude" in the words of Gordon Gullion. The size of the frontal shield in European coots is also correlated with gonadal size. The frontal shield is apparently used for individual recognition and it is an important in territorial disputes or fights. When an intruder enters a territory, the resident bird will lower its head, raise its wings and prominently displaying their shield to the intruder. Like so...

A typical posture of an aggressive coot

I have much more on stock on Coots, but this will have to do for today.

More information
Visser, J. (1988). Seasonal changes in shield size in the Coot Ardea, 76, 56-63

Gordon W. Gullion (1951). The Frontal Shield of the American Coot The Wilson Bulletin, 63, 157-166