Wednesday, April 5, 2017

Fish eating birds

How many kinds of birds eat fish, and what different methods they use to catch their slippery prey?
Like Kingfishers, Ospreys spot their prey from the air and plunge in to get it, but Ospreys plunge feet first, while kingfishers go in headfirst. Belted kingfishers are winter residents in West Texas, while Green Kingfishers live year around in the Pecos River as far north as Iraan. Ospreys visit the region every fall.
Terns hover with rapid wingbeats until they spot a school of fish just below the water’s surface, then dive in head first and swim underwater until they snatch their prey. Several species of terns visit West Texas during migration.  Gulls much prefer to rob terns of their fish rather than working to capture their own, but plunge feet first like Ospreys when they must. A half dozen species of gulls are regular visitors to the water impoundments of the Llano Estacado and Chihuahuan desert.
The two North American Pelicans differ in their methods of fishing. The Brown Pelican spots his fish from the air, and dives steeply head first from as high as 70 feet. Sometimes he submerges completely, sometimes only partly, but he comes up with a pouch full-of fish. Brown pelicans visit the region rarely, but as their numbers have improved, their visitation has increased in the
A White Pelican that has spotted a fish from the air lands with a splash, feet forward, then ducks its head under and scoops up the fish. White Pelicans also practice cooperative fishing – a group of half a dozen or more birds line up in a semicircle facing shore. They flap their wings and splash vigorously, driving the fish ahead of them into shallow-water where they can be easily caught. White Pelicans are winter residents in many lakes along the rivers of the region.
Bald eagles have slowly been increasing, and in recent years have spent time at some of the regional lakes. They catch fish like an Osprey, feet first. Most sightings have been on the eastern and northern edges of the Llano.
The wintering fish eaters, such as loons, and mergansers as well as some of the summer nesting grebes and cormorants dive underwater from the surface, finding a fish only after they’re under water.  Cormorants have long cutting bills ending in a strong hook, with which they hang on firmly to their prey until they get it to the surface. Mergansers have saw-like edges to their bills and horny bristles on their tongues to facilitate, grasping a fish. Mergansers also herd fish like White Pelican.
Herons and egrets may stand quietly at the edge of the water, waiting for
a fish to swim by. With a sudden jab of their long bills they grab or spear the
fish. But herons have another fishing behavior: foot-paddling. They walk slowly in shallow water, then stop and extend one foot with which they either rake the bottom or stir the water. This disturbs the fish, which darts out of hiding and is grabbed by the heron.
Green herons have learned to stand with their wings spread on a sunny day, and remain motionless until a fish senses the cooler water of the shade and swim to what appears to be a safe shady hiding spot.
Songbirds occasionally enjoy fishing. Robins, Brewer’s Blackbirds, Gray Catbirds, Say’s Pheobes, and Louisiana Water thrushes have been seen catching small fish at the water’s edge. Kiskadees, normally insect eating flycatchers, also sometimes catch fish. Kiskadees are rare in the region, but sightings have become more common in the last decade.

No comments:

Post a Comment