Red Tailed Hawks

Red-tailed hawks, Buteo jamaicensis, are one of the most common and widespread hawks of North America They get their genus name from the Buteo genus of hawks which are known for their sturdy body and broad wings. Their species name comes from the island of Jamaica, where they were first studied scientifically. Besides North America, these hawks can be found in Central America and some Caribbean islands, including Cuba and the U.S. Virgin Islands.

Red-Tailed Hawk Range, nationalgeographic.com

Red-tailed hawks get their familiar name from the rusty brown tail sported by the adult hawks. It is easy to identify an adult either from the air or when perched. The underbelly is white with a broad band of dark brown horizontal streaks across the middle. The beak is short and dark, while the legs, cere and feet are yellow. Generally, birds that are under two years old have bands of brown and white on the tail and develop the classic red tail in their third year.

RedTailedHawk, amherst.edu

Red-tails are most often found in open habitats such as roadsides, fields and power lines, which provide an excellent vantage for sighting prey. They are also frequently seen perching on light fixtures and telephone poles along roadways. They soar in slow circles as they climb skyward on thermal updrafts. You may see a bird suddenly stop or seem to hover from a great distance above the ground and then dive straight down to the ground to capture an unwitting animal.
If you hear some blue jays or crows yakking away, it might be because they have spotted a red-tail ( or a Great Horned Owl ) and are harassing it. This behavior is called “mobbing”.  The goal of mobbing birds is to drive the hawk away from either their young or from food sources both species are competing for. With blue jays, at least to me, it seems like they do it many times just for fun. Usually the hawks simply stay put until the crows tire of their efforts. Or the hawk may have enough and fly to another area. Only once have I ever seen a red-tail respond to mobbing birds by grabbing an unfortunate crow with its talons and dropping the body to the ground. The rest of the crows quickly dispersed and lived to see another day.
Red-tails are generalist and opportunistic feeders, taking whatever prey presents itself. Small mammals such as voles, mice, chipmunks and red squirrels are frequent targets. They will also prey upon other birds, gray squirrels, rabbits, and baby woodchucks. I have seen a juvenile red-tail try to prey on two very large carp that were trapped by debris in a swollen stream bed one spring. From its perch on a small alder situated on the stream bank just above the two fish, the young hawk would jump down upon the backs of the carp. Of course this caused the surprised fish to flop mightily about and the hawk became unsure of what to do. It would retreat back into the tree and try again. This went on for quite a while, and I don’t know if the hawk gave up or finally got its meal. The only reason I even got a chance to watch this drama was because two mallards were quacking up a storm, alarmed by of the presence of the hawk, and I went off a trail to see what the commotion was about.

Young red-tail ‘fishing’, photo by Pamm Cooper

One thing to note about buteos is that the female bird is noticeably larger that the male. Red –tail hawks mate for life and both parents are involved in feeding their young. Males feed their mate while she is sitting on the eggs, usually for 30- 32 days. Eggs hatch a few days apart, so all fledglings are not the same size. One may be considerably delayed leaving the nest while older siblings are already able to fly. Usually in the North East, two or possibly three eggs will be laid. Fledglings leave the nest after 40-46 days after hatching. They will fly after another two or three weeks and start catching their own food 6-7 weeks after that.

Eye-ridge of red-tail, paw.org
Hawks can see a mouse from a height of 100 feet and there is a bony ridge above the eyes that helps block the sun.

A good book about red-tailed hawks is: “ Red-Tails in Love: a Wildlife Drama in Central Park ” written by Marie Winn and published by Pantheon. This book is a true story about a pair of red-tailed hawks that nest on Fifth Avenue in New York City and the band of bird-watchers who become ardent followers of these two birds. It describes the hawk’s courtship, mating and struggle to survive in the big city environment and the ways in which their devoted fans try to help them.
For good information on northern birds, the University of Cornell Lab of Ornithology, the American Ornithologist’s Union, and the Academy of Natural sciences worked together on a comprehensive reference, “ The Birds of North America “. Cornell’s lab of Ornithology also has an excellent website that is well worth exploring.

-Pamm Cooper
Sources:
Pennsylvania State University
The Cornell Lab of Ornithology
Ohio State University

 

The Lowly Earthworm

Pile of earthworms. Urbanext.illinois.edu

The soils supporting our home lawns, vegetable and perennial gardens are improved by the presence and activity of earthworms. They are considered beneficial in the plant world. Earthworms move through the layers of soil creating tunnels for water and oxygen to reach the plant roots and channels for root growth. Their movement increases drainage and reduces compaction. Often called “nature’s rototillers”, earthworms feed on organic matter, bacteria, fungi and small soil particles in varying depths depositing their castings, or feces, in other horizons effectively turning the soil over. Castings are rich in nitrogen and nutrients easily absorbed by plants. Their feeding aids decomposition of organic matter, aerates soil, creates good soil structure and develops humus. The Rothamsted Experimental Station in England has done research finding as many as 250,000 earthworms per acre. That is a lot of subterranean work happening! Charles Darwin was one of the first scientists to recognize the benefits of earthworms. His last book written in 1882 is on the worm biology and behavior. His discoveries of earthworms are still being seen today.

Often after a rain, earthworms come to the soil surface then re-enter the ground head first. Some scientist think the worms come to surface for air if the ground is saturated. Others believe chemicals in the rain are inhospitable by changing pH and chemical amounts from acid rain. Still others think since the surface is moist, the worms come to the surface to mate. Earthworms are negatively affected by drying out by the sun therefore most surfacing happens at night. The action of tunneling back into the ground squeezes the worm leaving a pile of castings above ground. The casting look like tiny round balls piled up in a pyramid up to two inches depending on the size and type of the worm. Casting piles normally go unnoticed unless the turf is cut exceptionally short like that on golf course greens and tees. Home lawns should be cut to a height of at least three inches. Wet piles can stick to mowing equipment gumming up the blades and gears. The piles are easily dispersed once they dry.

Earthworms breathe through their skin. Oxygen is absorbed by mucous on the outside surface of the worm where it is transferred to the internal organs. This is called a gas exchange. The circulatory system of the earthworm contains five hearts or aortic arches. They pump fluids to blood vessels and capillary beds throughout the body circulating back to the hearts. The earthworm’s digestive system starts with its wide opening of a mouth that its throat or pharynx protrudes out of grabbing organic matter, soil particles and all that they contain. This food is swallowed down to a storage area called a crop. The food then moves to the gizzard where it is ground up by strong muscles and tiny stones and grit swallowed by the worm. Once the food is sufficiently ground, it moves to the intestines where digestive juices extract nutrients and some are absorbed by the worm. Excess digested food is then excreted as worm castings. It is these castings that are rich in nutrients readily available for plant roots to pick up. Earthworms don’t have eyes but are sensitive to light, vibration, touch and chemicals. They want to be in darkness and will move away from the light.

Chemicals added to lawn and garden can kill the earthworms. Preferred pH levels are neutral to 6.6. Adding lime in large doses can be too shocking of a change in their environment. Many earthworms will move to areas with better suited conditions or they may just die. Some insecticides and fungicides have lethal effects on earthworms. Researchers have also found earthworms within chemically treated soils to contain up to 20 times the toxin levels than the soil the worms inhabited. Stored toxins built up in the earthworms could then be passed up the food chain to animals using the earthworms as food.

Earthworms are classified as animal invertebrates. They are in the phylum group Annelida, meaning segmented worms.   Each segment contains four tiny setae or claw like bristles used to move through the soil.  Worms are hermaphroditic;  each worm has both male and female parts with the male pores located on the outside of the animal. Earthworms are not self fertile. They need another worm to mate and reproduce. Each worm is fertilized in the mating process called cross-fertilization.

The most common earthworms found in Connecticut are Lumbricus terrestris, called the Night Crawler, and Lumbricus rubellus called Red Worm. Night crawlers are known to venture deep into the soil in permanent vertical burrows. The will come to the surface to feed also. Red worms prefer to live in a manure pile or area with high organic matter. Both of these earthworms originated in Europe and were introduced to North America unknowingly on plant material, ship ballast, wheels and shoes of immigrants. Native earthworm finding are very rare. It is not known whether native types were wiped out by glaciers scraping the earth or if the new earthworm invaders displaced the old. Different theories exist. What is known is that the earthworms that are present today are many, active and busy decomposing and recycling organic matter in rich new topsoil.

There are some invasive worms originating from Asia that are causing problem in some areas of North America. They are such fast consumers of organic material they are changing the layers of soil and eliminating the forest floor called ‘duff’. Some birds nest in the duff areas to raise their young. Insects and animals that also reside and feed in the fast disappearing habitat are also finding it hard to live. The effect of the exotic worms in the local habitat really is upsetting the ecological balance. Some populations that depend on the areas the worms are ruining might vanish forever. Research is presently being done but much more needs to happen. So does education of the general public. Some fishermen are using invasive worms for bait, then just dumping the leftovers on the ground. They are unknowingly spread the invaders. ATV and off-road enthusiasts also can pick up soil, worms and eggs in tire treads, then depositing them far from the initial infected site. Hopefully in the not too far future, more information and education programs will be available. Keep watching!

-Carol Quish

 

 

Owls in January

Great Horned Owl HopiakCLO photo

Recently while visiting my daughter in Massachusetts, I heard the hooting of an owl breaking the silence of the night inside the house. Out on the deck, his call could be heard much more clearly. Her house abuts a large wetland filled with tall pines and maples. I looked up owl calls on the internet and identified the call as coming from a Great Horned Owl. Listen to several different owl calls at this link. owl calls

Great Horned Owls are plentiful in New England. They are known to eat around 250 different species of mammals , fish and reptiles. Lizards, frogs, fish and salamanders are wetland prey the owl I heard was probably seeking. Raccoons, squirrels and rodents are not safe from Great Horned Owls during their nocturnal hunts either. Other foods sources are large insects, crayfish, scorpions, centipedes,  worms, spiders, and road killed animals. The Great Horned Owl will regurgitate pellets of indigestible parts of animal six to ten hours after eating. Naturalists and scientists look for the pellets to dissect giving them clues to the owls’ diet.  I remember doing just that in an elementary school science class many years ago, and sparked my curiosity of owls.

The most recognizable feature of the Great Horned Owl, Bubo virginianus, is the tufts of feathers looking like horns or ears, called plumicorns. They are neither ears nor horns just longer feathers. The name plumicorn comes from the Latin pluma meaning feather and cornu meaning horn. The Great Horned Owl is a large bird 18 to 24 inches tall and can weigh over 5 pounds. They nest in hollow trees and cliffs or the abandoned nests of other large birds, preferring not to make their own. Mating season for an owl couple is January and February annually. The female will two or three eggs that will hatch in about four weeks. Both the mother and father will sit on the eggs and feed the owlets. Baby owls will venture out of the nest by hopping between one and two months old. They learn to fly around 10 weeks old. There is only one generation each year.

-Carol Quish

Owl Pellets, sfjc.edu