Toucans birds sizes from the Lettered Aracari(Pteroglossus inscriptus), at 130 g (4.6 oz) and 29 cm (11.5 inches), for the Toco Toucan (Ramphastos toco), at 680 g (1.5 lb) and 63 cm (29 inches). Their bodies are short (of comparable size to a crow's) and compact. The tail is rounded and varies in length, from half the length to the whole length of the body. The neck is short and thick. The wings are small, as they are forest-dwelling birds who only need to travel short distances, and are often of about the same span as the bill-tip-to-tail-tip measurements of the bird.The legs of the toucan are strong and rather short. Their toes are arranged in pairs with the first and fourth toes turned backward. The majority of toucans do not show any sexual dimorphism in their coloration, the genus Selenidera being the most notable exception to this rule. However, the bills of female toucans are usually shorter, deeper and sometimes straighter, giving more of a "blocky" impression compared to male bills. The feathers in the genus containing the largest toucans are generally black, with touches of white, yellow, and scarlet. The underparts of the araçaris (smaller toucans) are yellow, crossed by one or more black or red bands. The toucanets have mostly green plumage with blue markings.
The colorful and large bill, which in some large species measures more than half the length of the body, is the hallmark of toucans. Despite its size, the toucan's bill is very light, being composed of bone struts filled with spongy tissue of keratin between them. The bill has forward-facing serrations resembling teeth, which historically led naturalists to believe that toucans captured fish and were primarily carnivorous; today it is known that they eat mostly fruit. Researchers have discovered that the large bill of the toucan is a highly efficient thermoregulation system, though its size may still be advantageous in other ways.It does aid in their feeding behavior (as they sit in one spot and reach for all fruit in range, thereby reducing energy expenditure), and it has also been theorized that the bill may intimidate smaller birds, so that the toucan may plunder nests undisturbed (see Diet below). Also, the beak allows the bird to reach deep into tree-holes to access food unavailable to other birds, and also to ransack suspended nests built by smaller birds.
A toucan's tongue is long (up to 14–15 cm, or 6 inches), narrow, grey, and singularly frayed on each side, adding to its sensitivity as an organ of taste.These birds are arboreal and typically lay 2–4 white eggs in their nests. They make their nests in tree hollows and holes excavated by other animals such as woodpeckers—the toucan bill has very limited use as an excavation tool. When the eggs hatch, the young emerge completely naked, without any down. These are resident breeders and do not migrate. Toucans are usually found in pairs or small flocks. They sometimes fence with their bills and wrestle, which scientists hypothesize they do to establish dominance hierarchies.Toucans are primarily frugivorous (fruit eating), but are opportunistically omnivorous and will take prey such as insects and small lizards.for more birds.....
