BirdWalk Newsletter

Transcription

1 BirdWalk Newsletter Walk Conducted by Perry Nugent Newsletter Written by Jayne J. Matney Cover photo by Guenter Weber Little Blue Heron (Egretta caerulea) The Great Blue Herons and the Egrets get so much of the attention around here. There is another bird, the Little Blue Heron, who is so deserving of an ovation. The Little Blue Heron, or Lil Blues, are not as closely related to herons as they are to the egrets. They even tend to gravitate with the clusters of Snowy Egrets if they are not going solo, as they usually do. Actually, when they are in their first year, they are white like the egrets and use this to their advantage to stay in numbers with the egrets for a better survival rate. Therefore, many times you can be looking at a flock of egrets which have young Little Blue Heron mixed in and never realize it.

2 An immature Little Blue Heron Photo by Cathy Padgett After this first year time frame, they begin to develop an intermediate plumage of dappling white and slate blue. Eventually, their body plumage becomes a dazzling slate blue while the head and neck develop purple and burgundy hues. Their beak and leg colors also go through transformations. The beaks go from gray to blue, and have a black tip, while the base of the beak gets bright blue. The legs go from dull green-gray to more of a bluegreen in color. The legs are long and the wings are rounded. Their necks are long and pull back against the body in flight. Both male and female look the same. The aigrette plumes that originate on the head and flow down the back of the neck are more subtle in the Little Blue Herons. Photo by Cathy Padgett *Note adult breeding plumage and colors For that reason, their numbers did not suffer as badly when the decimation of the egrets and herons occurred for gathering of feather plumes for hats.

3 Unfortunately, according to the North American Breeding Bird Survey, Little Blue Herons today are in a 55% decline since They are now on the North America s Birds Watch List and are on the North American Waterbird Conservation Plan as a High Concern species. They are suspected of being highly Photo by Cathy Padgett vulnerable to problems with water quality, human disturbance, and habitat destruction. They are now protected under the Migratory Bird Treaty Act. Ranging from New England to Florida, and the Gulf Coast through the Caribbean and tropics, they are generally found in fresh water swamps, ponds, lagoons, marshes, and canals. Look for places that have access to shallow waters of 2 to 6 inches where these slow, methodical feeders can wade. Photo above: Jo Frkovich Nesting Lil Blue Photo left: Cathy Padgett

4 They can also be found in farmers fields when insects are being stirred up from the ground or standing water has occurred. Lil Blues eat mostly fish and amphibians, but they also readily eat crustaceans, and larger insects such as dragonflies, crickets, and grasshoppers. Small reptiles, crayfish, and crabs have also been known to be on their menu. Rather than spearing their prey as a Great Blue Heron would do, the Little Blue Heron will grab ahold of prey by their beak. A young (note the white plumage and gray-blue beak) Little Blue Heron with crayfish in beak

5 Photo by Chuck Fuhrman They usually prefer to nest alone or along the peripheral of egret colonies. The males generally choose the spot close to water with trees or tall brush. When the females come into the area, the males will begin displaying by fluffing out with beautiful fans of feathers. He will hold his head up high and straight upward. He may soon begin to compress his body then snap his beaks together. The waving of sticks and branches have also been seen as a behavior to attract the mate. Their interaction may be aggressive at the start, but eventually

6 they will lean close to each other and intertwine their necks. The building of the nest is done by both parents as is the raising and care for the young. The male is usually the retriever of the sticks and the female is the one putting the nest together. 2-5 powder blue-green eggs are the clutch size for these birds. Incubation is between days. Once the young hatch, both parents feed by regurgitating food to them. Flight lessons begin around the 4 week time frame and independence is acquired by 7 weeks of age. Photo by Jo Frkovich

7 Fun Facts: 1. When the Little Blue Heron are not here, they are sometimes migrating north before they head back down for the winter. 2. Although they usually prefer not to colonize, some of the larger colonies of Little Blue Heron can be found in the lower Mississippi Valley. 3. The life span for an ordinary Little Blue Heron is up to seven years of age. However, the oldest known Little Blue Heron was noted to be at least 13 years and 11 months old. It was first banded in Virginia in 1957 then found in 1971 in Maryland. 4. The intermediate stage of plumage (white and slate blue feathers) is sometimes called Calico, Pied, or Piebald by birdwatchers. 5. Most birds are known for preening with their bills. Sliding the bills through to realign and arrange their feathers. However, you may see a Little Blue Heron with a foot up high and sliding downward along the feathers. That is because they have a built in comb on the middle toe of their foot! Sources for this newsletter were: The Cornell Lab of Ornithology, All About Birds ; Audubon Field Guide, Little Blue Heron, Kenn Kaufman; Nature Works, Little Blue Heron. Photo by Jo Frkovich

8 Sunday, July 9 th : The Little Blue Herons were very busy, in full view, and in large numbers this week. The nesting Lil Blues are beginning to gather the growing young and give them flight lessons. The adult birds fly out from the branch in a complete circle and return to the starting point. The more daring of the young will then mimic (or tries to mimic) the parent. It takes a bit of practice and can be quite comical to watch as the practicing young birds may steer off in the wrong direction, or make an awkward, warped circle, and/or crash land. Approximately 50 individuals of this type of bird were pursuing these early summer activities. While they were feeding, teaching, and learning life skills, other birds were seen nearby. Anhinga, Great Blue Heron, Cattle Egret, Great Egret, Snowy Egret, Tricolored Heron, Black-crowned Night Heron, Wood Duck, Common Moorhen, and American Coot showed up. Also found specifically in the large impoundment was a Pied-billed Grebe. Flyover sightings included a single Wood Stork, White Ibis in a V formation, and Laughing Gull. Double Crested Cormorants were seen from the river dike. 2 Black Vulture and 12 Turkey Vulture were scoping out the area. A Mississippi Kite was viewed in flight between the house and the office. Our more common hawks were seen and heard- the Red-shouldered and the Red-tailed Hawks. 3 Yellow-billed Cuckoo were seen in the woods between Ravenswood and the Carriage House. Also seen in these woods was a Ruby-throated Hummingbird. Across the dike from Ravenswood was a solo male deer. The entrance road revealed Great-crested Flycatcher and the White-eyed Vireo. Summer Tanager and Yellowthroated Warbler were found along the exit road. In the Audubon Swamp, the Prothonotary Warbler and the Common Yellow-throat were located. Photo by Ray Swagerty

9 Prothonotary Warbler Photo by Guenter Weber A bobcat sitting in the brush caught the birdwatcher s eye as the cat turned its head, then in a flash, it was gone into the swamp near the cemetery. An Eastern Bluebird showed itself at the Pavilion field. 3 young Indigo Bunting, which were not yet in adult plumage but rather greenish in tones, were observed near the cabins in the brush. In the woodpecker family, the Red-bellied, the Downy, and the Pileated were all represented. Rounding out the field were: Mourning Dove, Blue-jay, American and Fish Crow, Carolina Chickadee, Tufted Titmouse, Carolina Wren, Blue-gray Gnatcatcher, Northern Mockingbird, Northern Cardinal, Red-winged Blackbirds, and the Common and Boat-tailed Grackles.