Tuesday, 18 August 2015

The first of the migrating Pochards have arrived on the lake. Yesterday, when I did the monthly bird count, I found 40 of them, almost all drakes. The sexes migrate separately, the males going first. There were also 19 Red-Crested Pochards, but these are residents and wander around the London lakes apparently at random.

You can get a better view of the Great Crested Grebes' nest on the fallen poplar in the Long Water by standing on the Vista and looking through the bushes. Most of this soggy heap is made of Horned Pondweed, the most readily available material at the moment and a bit stronger than the usual green algae.

Two studies in flying: a Tufted Duck has to take a little run across the water to reach takeoff speed, unlike a Mallard which can leap into the air from a standing start.

And here is a Grey Heron about to touch down on a branch. It has braked to lose flying speed and its wings have stalled, and the turbulent airflow is buffeting its feathers all over the place.

Three young Pied Wagtails were sprinting around on the lawn in front of the Orangery. The carefully manicured turf allows them to run at full speed -- not that this one needed to run very fast to catch its worm.

In a patch of long grass beside the Round Pond, a male adult was having to leap into the air to move around among the obstructing stems. However, this allowed it to catch a fly in the air. Probably the young ones have not yet learnt that considerable skill.

You don't often see a Carrion Crow being unselfish, even to its own young when they have fledged. I gave the adult two peanuts, and it walked over to the young one and offered it one of them, and they demolished them happily side by side.

One of the Little owlets was in the nest tree, and gave me a curious sidelong glance.

Its father was in the maple tree, and couldn't be bothered to look down at the familiar sight of humans taking pictures.


  1. Good afternoon Ralph. I wondered why cygnets sometimes swim with one leg stuck out at the back or tucked up on their back or under a wing, out of the water. Suggestions include temperature regulation (both heating up and cooling down, but not sure how that would work), and doing the Hokey Cokey (I am not sure that last one was entirely serious). Do you know please?

    1. Both young and adult swans often swim with one leg while the other is tucked up. So do grebes. The reason that you notice this with cygnets is that they have little undeveloped wings which don't hide their legs. The reason, surely, must be the simple one that when they aren't in a hurry there's no point in using two legs when one will do.

    2. Yes, a labour saving device makes sense. They do look very appealing when they are doing it! Thank you.

    3. PS from the RSPB site:

      "Swans will often stretch one of their legs whilst swimming and instead of putting it in the water, they will tuck it up onto their back.

      It has been suggested that this behaviour may play a role in helping to regulate the body temperature of the bird. The legs and feet are the only part of the swan not covered in feathers so the blood vessels are in closer contact with the air. The large surface area of the webbed foot makes it easier for heat to be transferred from the body to the air, cooling the swan. This heat exchange could also work the other way, with the feet absorbing heat from the air to warm the bird."

      Both explanations could be correct of course!

    4. There could even be a third reason:

      "The Australian black swan has been noted to only swim with one leg, the other being tucked above it's tail. This helps the swan to change direction more smoothly when the swan is swimming on the surface of the water, should the swan spot food or even an oncoming predator."

    5. I wonder what the predators of Black Swans are -- alligators? You would think that if the swans needed to make a hasty escape, having both feet in the water would be a good idea.