Readers’ wildlife photos

Today we have another batch of fantastic photos of peregrine falcons taken by Bruce Lyon. It even has a title! His text is indented.

Peregrines during Jerry’s peregrinations

Jerry’s put up previous posts on these bird s(see here, here, here, here, and here), and it’s nesting season again for the pair of peregrine falcons (Falco peregrinus) I have been observing for the past four years along the California coast between Santa Cruz and San Francisco. Every year the pair has nested in a small cave in a cliff above the ocean. This year I was lucky enough to watch the female lay her first egg in mid-March. This post, however, is about last year’s nest, but I include a photo of the normal cave nest site to put last year’s turn of events into perspective.

Below: March of this year—the female walks to the nest with three eggs at the back of the small cave; the next day she laid a fourth egg and the both adults have since shared in incubation. When walking to the eggs the falcons resemble parrots which is not that surprising since we have learned in the past decade that the falcons are close to parrots on the avian family tree (and not related to hawks and eagles).

Last year, the birds nested in the same cave they used in the two previous years, but that nest was not successful, for unknown reasons (the eggs disappeared between my weekly visits). Previous studies of peregrines in central California found that they will often have a second nesting attempt after a failed first nest. My birds did eventually re-nest but they shocked me by their choice of nest site. The second nest was a tiny open shelf at the top of the cliff, at eye level and very close to where I always sit to observe the birds! It does not get better than this from a natural history perspective—tame falcons nesting at eye level in an open photogenic spot.

Below: The male settling in to incubate the three chestnut eggs. I find the egg color quite beautiful.

Below: A close-up of the male turning the eggs.

Below:  The female was snoozing when the male showed up to take a turn at incubation. The fact that she was snoozing while I sat 40 feet away shows how comfortable the birds had become with me. Perhaps they see me as just another dumb cow on the landscape.

Below: The male’s sudden arrival startled the sleeping female; she started to fall over and had to spread her wings to maintain balance.

Below: The female with two fairly recent hatchlings.

Below: Ten days later the male checks out the one surviving chick. The brood was quickly reduced to one chick, presumably due to limited food. Some starvation is normal in falcons, and peregrines and many other birds have a mechanism to efficiently cull the brood size (“brood reduction”) if it turns out they laid an overly optimistic number of eggs. They create an asynchronous hatch by starting incubating the eggs before all have been laid. This gives the early eggs a head start and a competitive advantage should food be limiting.

The adults each have their roles and the female seems to be the one who controls food at the nest. Whenever the male brought food directly to the nest she would rush to the nest to get the food from him. The sequence of photos below shows such an encounter. The male showed up with a freshly killed female red-winged blackbird and perched for a bit on a nearby rock before flying to the nest. As soon as he went to the nest the female showed up within seconds. The male then took off with the prey item, with the female following in hot pursuit. She eventually got the blackbird from him in an aerial transfer and then returned to the nest with it. Amusingly, the chick then stole the prey item from her and it took her a few minutes to get it back from the chick.

Below: The male perched next to the nest with a female red-winged blackbird.

Below: Before the male could even land at the nest with the prey the female showed up, causing him to take off with the meal.

Below: As the chick got older it started to harass the parents, perhaps telling them it was hungry and that they should go at get some dinner for it. Here the chick has rushed the female who was perched at the nest and she complains and decides to leave.

Below: Another example where the male showed up at the nest with prey, only to have the female arrive within seconds and cause the male to leave. In this particular encounter, I had watched the pair kill the prey item about half an hour earlier. The male and female went after a mourning dove that they had watched go in and roost in a bush on a hillside several hundred yards (meters) away from the nest. The female flushed the dove from the bush and the male then nailed it. This photo was taken in the evening and had lovely backlighting, an effect I am very fond of.

Below: The chick five days before fledgling. It is hanging onto a branch while flapping furiously, presumably to strengthen its flight muscles in preparation for real flight.