Stéphane’s Blog for April 27, 2015

The Day in the Life of a Bald Eagle!

In a very quiet day otherwise (only 3 birds were captured in 6 hours of banding!), we had the privilege to be spectator in the daily routines of our breeding eagles.

In spring, there is a seasonal creek that empties into Wingfield Basin, where the fish like to spawn. Consequently, the Bald Eagles like to perch on nearby tall trees or, even, on the ground near the creek. This morning, the fishing was successful. On one occasion, the male caught a fish and was soon joined in the air by the female, which had momentarily left the nest. They passed the fish in mid-air but the female missed the catch and the fish fell in the water. The female eagle went down to retrieve it but it must have been heavy: the eagle sat in the water for some seconds, trying to lift off without success. Finally, she managed to get airborne again and flew directly to the nest. An eagle half submerged in water is always a strange sight!

Later in the morning, the male eagle caught a fish and started eating it right next to the creek. It was immediately attended by a court of scavengers who stood at a respectful distance. The 2 American Crows were the bravest, staying close to the eagle, while the 2 Turkey Vultures bid their time a little farther away. As soon as the eagle had enough and fly away, leaving behind a sizeable chunk of fish, the crows were right on it, eager to gobble as much as possible in as little time as possible. And they should: one had barely enough time for a beakful, when a Common Raven swooped down from nowhere and displaced the crows without a problem. The vultures had not yet started to walk toward the query. The raven took its time to feed, then flew off with a big, red, blob in its beak, no doubt thinking of its youngsters in the nest. Seizing their chance, the lesser scavengers approached. This time, one Turkey Vulture was first on the fish and started eating while the crows tried to steal as many morsels as they could.

Icy view west from Cabot Head_April 27_2015The raven returned and pushed everyone away again. Again, it flew off with a big chunk. So, the American crows and, this time, the 2 Turkey Vultures resumed scavenging. But the raven returned once more and got prime access once again. Then, the eagle came around to show who is the real boss and everyone scattered. The crows soon crept back very close: they have to if they want to snatch something. The eagle flew to a nearby rock and all the scavengers returned. There are now 3 crows and 3 vultures, but a Herring Gull finally arrived. It chased off a crow successfully for some very unappetizing (to a human eye) bit of food. It perched on a small piece of ice in the basin and gave a long call. Another herring gull joined it, most likely answering the call, and they stood side by side and tried to share the food, without fighting. That morsel may not be very appetizing for a gull eye too, as they struggle to ingest it. They took off, one carrying the food in its beak.

So, when an eagle catches a fish, there is definitively a top-down chain reaction: on this occasion, 9 other birds of 4 different species benefitted from the eagle catch! This is the Canadian, feathered version of an African lion pride and their cohort of followers (jackals, hyenas, vultures, etc).

Bald eagles seem to be fairly tolerant to their own kind: there is now a third adult bald eagle hanging around the basin. While the female is sitting on the nest, the 2 other adults can be seen flying together or perched in trees not far from one another. However, there is a limit: when the “other” eagle perches on the favourite tree top of the breeding pair, it is promptly dislodged by the resident male; and without a fuss: the resident just flies toward the treetop, as it would for a normal landing, and the other eagle just takes off and flies away. Everybody knows their place.

Stéphane

 

 

 

 

Posted in STATION NOTES / BLOG