Anne Elliott's photos with the keyword: tree cavity

Feeling totally lethargic after Christmas Day and Boxing Day, I finally made myself go to Fish Creek Park two afternoons ago, on 27 December 2014. A few people had been seeing a fist-sized or popcan-sized Northern Pygmy-Owl recently and so I thought I'd go and see if anyone else was there and if they had found this tiny owl. In fact, there were two people there who were looking at the owl, perched way in the distance near the top of a very tall coniferous tree. It flew to another tall coniferous and to a tall, dead tree. The word "tall" is never a good word when it comes to searching for one of these tiny owls, lol. However, I was just thrilled to bits to see it at all. I think my first photos of this owl species were taken on 6 December 2007, At one point, the owl flew off and disappeared. We started walking in the rough direction that we thought it might have flown and stopped in our tracks when we heard a Pileated Woodpecker in the area. Thinking that maybe it had been harassed or annoyed by the owl's presence, we went to look for the Woodpecker. It flew to a dead tree and after a few minutes, made its way round the back of the tree and out of sight. There were several holes in the back and there it was, hiding inside one of them, peering out at regular intervals. This is a male Pileated, as it has a red moustache. The park paths were absolutely treacherous. I was wearing good ice grabbers on my winter boots and they did absolutely nothing. They simply slid over the remaining ice that had been covered with a light dusting of snow. It snowed here again last night, hopefully enough to create a solid layer to completely hide the ice. “Pileated woodpeckers, the largest woodpeckers in North America, hammer their heads into trees with a force of 15 mph, 20 times a second. So how do their heads not turn to mush? Thick muscles, sponge-like bones, and a third eyelid keep bird brains intact. "If you get hit hard in the head, you can break blood vessels behind the eye or traumatize nerves behind eye," said University of California Davis ophthalmologist Ivan Schwab. ‘Seeing patients in car accidents and knowing what woodpeckers do made me wonder why these injuries don't happen in woodpeckers.’ Last fall, Schwab was honored with an Ig Nobel award, the irreverent version of the Nobel Prize, for his research on how woodpeckers avoid headaches, published in the British Journal of Ophthalmology. Along with their straight-as-an-arrow strikes at the tree, which safeguards against head trauma, birds' bodies are designed to absorb the impact. One millisecond before a strike comes across the bill, dense muscles in the neck contract, and the bird closes its thick inner eyelid. Some of the force radiates down the neck muscles and protects the skull from a full blow. A compressible bone in the skull offers cushion, too. Meanwhile, the bird's closed eyelid shields the eye from any pieces of wood bouncing off the tree and holds the eyeball in place. The eyelid acts like a seat belt and keeps the eye from literally popping out of the head," Schwab told LiveScience. "Otherwise, acceleration would tear the retina." The outside portion of the eye itself is firm, filled with blood to support the retina from being jostled around. Bird brains also remain rigid during head banging. Injuries to the human head make our brains bounce back and forth in the cerebral spinal fluid, bathing the organ, but woodpeckers have virtually none of this fluid. While scientists can't be certain that woodpeckers don't get headaches, Schwab pointed out that the birds are at least very tolerant of headaches.” From Science on NBC News, 1 August 2007. www.nbcnews.com/id/16531772/ns/technology_and_science-sci... www.allaboutbirds.org/guide/pileated_woodpecker/id "This Woodpecker is roughly Crow-sized ... Adults are 40 to 49 cm (16 to 19 in) long, span 66 to 75 cm (26 to 30 in) across the wings and weigh 250 to 400 g (8.8 to 14.1 oz), with an average weight of 300 g (11 oz)." From WIkipedia. en.wikipedia.org/wiki/Pileated_woodpecker

This beautiful female Northern Flicker was busy building a nest in this tree cavity, on 22 April 2014, at Carburn Park. "Both sexes help with nest excavation. The entrance hole is about 3 inches in diameter, and the cavity is 13-16 inches deep. The cavity widens at bottom to make room for eggs and the incubating adult. Inside, the cavity is bare except for a bed of wood chips for the eggs and chicks to rest on. Once nestlings are about 17 days old, they begin clinging to the cavity wall rather than lying on the floor. Northern Flickers usually excavate nest holes in dead or diseased tree trunks or large branches. In northern North America look for nests in trembling aspens, which are susceptible to a heartrot that makes for easy excavation. Unlike many woodpeckers, flickers often reuse cavities that they or another species excavated in a previous year. Nests are generally placed 6-15 feet off the ground, but on rare occasions can be over 100 feet high. Northern Flickers have been known to nest in old burrows of Belted Kingfishers or Bank Swallows." From AllAboutBirds. www.allaboutbirds.org/guide/northern_flicker/lifehistory en.wikipedia.org/wiki/Northern_Flicker