Birds of the Week # 7
Crows have been noted to be intelligent. They have the same brain-weight-to-body ratio as humans. This has led to some studies that have identified that crows are self-aware and that young crows take time to learn from tolerant parents. While a human has a neocortex, the crow has a different area in their brain that is equally complex. The average lifespan of the American crow in the wild is 7–8 years. Captive birds are known to have lived up to 30 years.
The most critical period of feather molting runs from late August to early September. When viewed in flight, they have a misaligned or “moth-eaten” appearance and generally slower and more laborious travel. Their mobility is reduced due to the lack of several remiges or rectrices or these are not entirely renewed. Most of the Red-winged Blackbirds have moved almost entirely by October. By then, some birds have not completed the molt of the feathers of the capital region and the helmsmen of the center of the tail and the internal secondary sprouts have only partially emerged from the pod. Virtually all individuals have completed their molts by mid-October.
Birds do not begin their migration to wintering quarters until the two outer primary sprouts and the two inner or central rectrices have completed at least two-thirds of their development. Therefore, there is a correlation between molting, particularly replacement of the remiges and rectrices, and fall migration in red-winged blackbirds.
Common Grackles have a unique adaptation in the keel within their bill which allows them to crack and cut hard nuts or kernels. The keel projects downward from the horny palate and is sharper and more abrupt anterior. It extends below the level of the tomium and is used in a sawing motion to score open acorns or dried kernels. Large adductor muscle within their jaw compared to other icterids also makes this adaptation even more useful for opening hard seeds and acorns.
The European Starling family, Sturnidae, is an entirely Old World group apart from introductions elsewhere, with the greatest numbers of species in Southeast Asia and sub-Saharan Africa. The genus Sturnus is polyphyletic and relationships between its members are not fully resolved. The closest relation of the common starling is the spotless starling. The non-migratory spotless starling may be descended from a population of ancestral S. vulgaris that survived in an Iberian refugium during an Ice Age retreat, and mitochondrial gene studies suggest that it could be considered a subspecies of the common starling. There is more genetic variation between common starling populations than between the nominate common starling and the spotless starling. Although common starling remains are known from the Middle Pleistocene, part of the problem in resolving relationships in the Sturnidae is the paucity of the fossil record for the family as a whole.
Great Blue Heron
Notable features of Great Blue Herons include slaty (gray with a slight azure blue) flight feathers, red-brown thighs, and a paired red-brown and black stripe up the flanks; the neck is rusty-gray, with black and white streaking down the front; the head is paler, with a nearly white face, and a pair of black or slate plumes runs from just above the eye to the back of the head. The feathers on the lower neck are long and plume-like; it also has plumes on the lower back at the start of the breeding season. The bill is dull yellowish, becoming orange briefly at the start of the breeding season, and the lower legs are gray, also becoming orangey at the start of the breeding season. Immature birds are duller in color, with a dull blackish-gray crown, and the flank pattern is only weakly defined; they have no plumes, and the bill is dull gray-yellow.
Snowy Egrets eat fish, crustaceans, insects, small reptiles, snails, frogs, worms and crayfish. They stalk prey in shallow water, often running or shuffling their feet, flushing prey into view by swaying their heads, flicking their wings or vibrating their bills. They may also hover, or “dip-fish” by flying with their feet just above the water surface. Snowy egrets may also stand still and wait to ambush prey, or hunt for insects stirred up by domestic animals in open fields. They sometimes forage in mixed species groups.
© HJ Ruiz – Avian101