By now, most of us have seen our first robin of the year and also have seen and heard the flocks of geese heading north in their familiar V formation. My diaries tell me that both sightings are right on schedule. Another sighting for me has been a great blue heron.

After checking in diaries from previous years, I found that I usually see this bird about the middle of March. The earliest sighting for me was on February 7 in 2006. I read in several bird books that the blue heron winters over in most of their breeding range.

These herons usually disappear from Bradford County in late fall and return by the middle of March, which coincides with the freezing and thawing of the ponds.

The great blue heron belongs to the heron family, which includes herons, egrets and bitterns. Worldwide there are 63 species in the family and in North America there are 15 species, including two foreign visitors — the gray heron and the little egret. The introduced cattle egret is now well established in North and South America.

Herons are long-necked birds usually associated with water because they are wading birds. Their main foods are frogs, mice, fish and insects. The blue heron does not spear its prey but grasps it between its long bills however larger fish are speared with the bill. Food is swallowed whole and later regurgitated in a pellet that contains items that the stomach juices cannot dissolve.

One year I was trying to trap a nuisance beaver to move it to a new home and accidently caught a blue heron in the foot trap. I had quite a tussle trying to release it. I had to hold the bird, while keeping away from its sharp bill and at the same time open, the foot trap.

Both egrets and herons have long legs, while bitterns are short-legged. The heron’s toes are not webbed like those of a duck. They fly with their legs straight back and their long necks tucked well in the back of their shoulders in an S shape. The similar long-legged and long-necked cranes, storks and ibises fly with their necks extended.

Egrets and herons will often curve their necks while standing in water, waiting for food to swim by. They stand straight-legged and move very slowly when wading, hardly making a ripple in the water. Sometimes, they will use a foot to stir or rake the bottom of a pond to flush prey from the mud.

An interesting note about the herons is that they will leave the water to defecate. They are always cleaning their feathers from two or three powder down patches, which appear as a powdery substance patch on the skin. Ornithologists believe that these patches are derived from disintegrating down feathers that persist on the birds throughout their lives.

The great blue heron is the best known and most widespread heron in all of North America. Many people refer to these birds as blue cranes. The other large heron, in North America, is the great white heron that is found in Florida, however it is believed by some to be a white phase of the great blue heron.

These herons stand four-feet tall, with a wingspan of up to seven feet. Although the male and female are similar, the male is slightly larger.

Blue herons are most active just before dawn and again at dusk, however they can be seen hunting at any time of the day. Although blue herons are most often seen near water, they also hunt in wet fields, sometimes far away from water.

Blue herons will nest in colonies known as rookeries, which range from a few nests — an average of 15 — to several hundred nests. The largest rookeries are found in the glaciated northern corner of the state.

Many years ago I had been told about a rookery located in my district here in Bradford County. After the first visit to the rookery Mary Alice never went back, however I returned several times. This rookery was located near the top of a hill, with no water nearby. The nests were built far out on the tree limbs, and many nests were built on the same tree. The nests, which were flat, flimsy platforms made of sticks about 18 inches wide, were quite flimsy, appearing as if the young could fall through.

The nests were used each year, and through the years, they became three to four feet across. Every year old nests were repaired, and a few new nests were built. I read in a bird book that the male brings the nesting material to the site, and the female places it in the nest.

After the birds pair up, they become quite protective of their nest site. If another bird gets too close to the nest, a battle will break out.

The female will lay four bluish-green eggs and incubation, which takes 28 days, is done by both male and female. At first the young are fed regurgitated food and later, solid food is placed in the nest, where it is picked up by the young.

The young grow fast, but remain at or near the nest site until they are as large as their parents. The young appear as they climb out on the tree branches. Occasionally, one will fall to the ground, resulting in death because the parents will not feed the young while they are on the ground.

The ground beneath the nests becomes covered with whitewash because both the young and old birds produce much excrement. This, along with decaying fish parts, produces quite an offensive odor. When walking near a rookery, one can hear the whitewash hitting the trees and ground.

All of the vegetation, even some young trees, will die from the whitewash. Egg remains of young from previous years are found under the trees. And this is the reason why Mary Alice never returned to the rookery site.

Bill Bower is a retired Pennsylvania Game Commission Wildlife Officer. Read his blog and listen to his podcasts on the outdoors at www.onemaningreen.com.