THE CROWPART 4 Dearfriends, I amreally happy over the large number of responses I have received about myposting about crow. I have posted already part 1-3 about crow. This is part 4 about crow.
Sincerely, Gopalakrishnan 8-3-2011. Reposted on 22-2-2021after editing and updating. R. Gopala Krishnan Continuing from part 3 22 Blue crow-Azure jay The AzureJay or blue crow is a passeri form bird of the crow family Corvidae. It is found in the AtlanticForest, especially with Araucaria angustifolia, in south-easternBrazil far eastern Paraguay and far north-eastern Argentina. It is the state bird of Paraná. It has atotal length of approximately 40 cm, and its plumage is intensely blue with a contrasting blackhead and upper chest. Males and females are similar, although the females typically are smaller. It feedsextensively on the nut-like seeds but it is not strictly limited to this, sinceit also feeds on insects and fruit. As other corvids, Azure Jays are highly intelligent. Theircommunication is complex, consisting of at least 14 distinct vocalizations.They form groups of 4 to 15 individuals that are well organized in hierarchies.These groups remain stable for up to two generations. I havetaken this information told in wikipdia for four important points. 1. Intelligentnature 2. Group formation limited 3. Communication method 4. Life span Veryoften among the crows I have observed this group forming. The nature of cawingtoo differ, when they have a problem and when food is available. I have observed theirintelligence by keeping their reserve of food with limited cawing.In the evening I have observed if more biscuits are given, they take two orthree, and consume the remaining in the morning. Though we cannot say the samecrows, but with similarity with appearance it is felt so. 23 Fossil records The earliestcorvid (crow family) fossils date to the mid-Miocene, about 17 MILLION YEARS ago; Miocorvus and Miopica of Francemay be ancestral to crows 24 Morphology Corvids(Birds of crow family) are large to very large passerines with a robust build, strong legs and all speciesexcept the Pinyon Jay have nostrils covered by bristle-likefeathers. Manycorvids of temperate zones have mainly black or blue coloured plumage; however, some are pied blackand white, some have a blue-purple iridescence and many tropical species arebrightly coloured. Thesexes are very similar in color and size. Corvids have strong, stout bills andlarge wingspans. The family includes the largest members of the passerine order.The smallest corvid isthe Dwarf Jay (Aphelocoma nana), at40 g and 21.5 cm. The largest corvids are the Common Raven (Corvus corax) and the Thick-billedRaven (Corvus crassirostris), both of which regularly exceed 1400 grams and 65 cm(26 inches). Speciescan be identified based on size, shape, and geography; however, some,especially the Australiancrows, are best identified by their raucous calls. 25.Ecology Corvidsoccur in most climatic zones. Most are sedentary and do not migrate significantly. However, during a shortage offood, eruptive migration can occur. When species are migratory, they will formlarge flocks in the fall (around August in the northernhemisphere)and travel south. One reason for the success of crows, compared toravens, is their ability to OVERLAP BREEDING TERRITORY. During breeding season, crows were shown tooverlap breeding territory six times as much as ravens. This invasion ofbreeding ranges allowed a related increase in local population density. 26 Food and feeding Corvids are highlyopportunistic foragers. The natural diet of many corvidspecies is omnivorous, consisting of invertebrates, nestlings, small mammals, berries, fruits, seeds, and carrion. However, some corvids, especially the crows,have adapted WELL TO HUMANCONDITIONS AND HAVE COME TO RELY ON ANTHROPOGENIC FOODS. In a studymade Common Ravens and Steller's Jays around camp grounds and humansettlements, the crows appeared to have the most diverse diet of all, taking anthropogenicfoods such as bread, spaghetti, fried potatoes, dogfood, sandwiches, and livestock feed. My note- I have tried dogbiscuit but I found they were not interested. Theincrease in available anthropogenic food sources is contributing to populationincrease in some corvid species. Some corvids are predators of other birds.During the wintering months, corvids typically form foraging flocks. However, some crows also eat many agriculturalpests including cutworms, wireworms, grasshoppers, and harmful weeds. Somecorvids will eat carrion, and SINCE THEY LACK A SPECIALIZED BEAK FOR TEARING INTO FLESH, THEY MUST WAITUNTIL ANIMALS ARE OPENED, WHETHER BY OTHER PREDATORS OR AS ROADKILL. 27. Reproduction Dear members, there was a mail to me from a member thatthey do not unite in open- special to crow. Some more attributes are there in theirmating when I read. So I better thought I will add them. Manyspecies of corvid are teritorial protecting territories throughout the year orsimply during the breeding season. In some cases territories may only beguarded during the day, withthe pair joining off-territory roosts at night. Thepartner bond in corvids is extremely strong and even lifelong in some species.THIS MONOGAMOUS LIFESTYLE, however, can still contain extra-pair copulations. Males and females build largenests together in trees or on ledges. The male will also feed the female during incubation. The nests areconstructed of a mass of bulky twigs lined with grass and bark. Corvids can lay between 3 and10 eggs, typically ranging between 4 and 7. The eggs are usually greenish in colour withbrown blotches. Once hatched, the youngremain in the nests for up to 6–10 weeks depending on the species. CORVIDS PROVIDE BIPARENTAL CARE. Mateselection is quite complex and accompanied with much social play in theCorvidae. Youngsters of social corvid species undergo a series of tests,including aerobatic feats, before being accepted as a mate by the opposite sex. 28.Social life Somecorvids have strong organization and community groups. Jackdaws, for example,have a strong social hierarchy, and are facultatively colonial during breeding.Providing mutual aid has also been recorded within many of the corvid species. Somecorvids can be aggressive. Blue Jays, for example, are well knownto attack anything that threatens their nest. Crows have been known to attackdogs, cats, ravens, and birds of prey. Most of the time these assaults takeplace as a distraction long enough to allow an opportunity for stealing food 29 Intelligence Thebrain-to-body weight ratios of corvid brains are among the largest inbirds, equal to that of great apes and cetaceans, and only slightly lower than a human. Theirintelligence is boosted by the long growing period of the young. By remainingwith the parents, the young have more opportunities to learn necessary skills.Since most corvids are cooperative brooders, their young can learn fromdifferent members of the group. Whencompared to dogs and cats in an experiment testing the ability to seek out foodaccording to three-dimensional clues, corvids out-performed the mammals. A metaanalysistesting how often birds invented new ways to acquire food in the wild foundcorvids the most innovative birds. A 2004 review suggests that their cognitive abilities are on par withthose of great apes. Despite structural differences, the brains of corvids andgreat apes both evolved the ability to make geometrical measurements. Somecorvids demonstrate the capacity for imagination, something believed to beotherwise unique to humans. I think long back our elders would have noted it andcrow is put to represent pithru Corvidingenuity is represented through their feeding skills, memorization abilities,use of tools, and group behaviour. Living in large social groups has long beenconnected with high cognitive ability. To live in a large group, a member mustbe able to recognize individuals and track the social position and foraging ofother members over time. Members must also be able to distinguish between sex,age, reproductive status, and dominance, and to update this informationconstantly. It might be that social complexity corresponds to their highcognition. TheEuropean Magpie is one of the few non-mammal species known to beable to recognize itself in a mirror test. There are also specific examples of corvidcleverness. One Carrion Crow wasdocumented to crack nuts by placing them on a crosswalk, letting the passingcars crack the shell, waiting for the light to turn red, and then safelyretrieving the contents. This phenomena appeared in a group posting also ,I recollect A group of crows in England took turns lifting garbage bin lids whiletheir companions collected food. Not in England, it is seen in India too.Many a day I have seen our waste box kept in the outside is lifted by one crowand others taking the feeds Members of the corvid familyhave been known to watch other birds, remember where they hide their food, thenreturn once the owner leaves. Corvids also move their food around betweenhiding places to avoid thievery, but only if they have previously been thievesthemselves i.e., they remember previous relevant social contexts, use their ownexperience of having been a thief to predict the behavior of a pilferer, andcan determine the safest course to protect their caches from being pilfered.Studies to assess similar cognitive abilities in apes have been inconclusive. The ability to hide foodrequires highly accurate spatial memories. Corvids have been recorded to recall their food's hiding place up tonine months later. Itis suggested that vertical landmarks (like trees) are used to rememberlocations. There has also been evidence that Western Scrub-Jays, which store perishable foods, not only rememberwhere they stored their food, but for how long. This has been compared toepisodic memory, previously thought unique to humans. This is what I first told of biscuits. 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