Question: Where are scales located on the bodies of birds?
About the article "Anatomy", section "Bird anatomy".

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Birds' scales are found mainly on the toes and metatarsus, but may be found further up on the ankle in some birds.
The scales and scutes of birds are thought to be homologous to those of reptiles and mammals. 
In snakes, the paraventral scales are the longitudinal rows of dorsal scales that contact the ventral scales.
These are the first rows of dorsal scales on either side of the body and are usually slightly larger than the scales located more dorsally.
In species that have mostly keeled scales, the paraventrals are usually smooth or only weakly keeled.
The term "paraventral" may also refer to the area on either side of the ventral scales. 
Integumentary system.
The scales of birds are composed of the same keratin as beaks, claws, and spurs.
They are found mainly on the toes and metatarsus, but may be found further up on the ankle in some birds.
Most bird scales do not overlap significantly, except in the cases of kingfishers and woodpeckers.
The scales and scutes of birds were originally thought to be homologous to those of reptiles and mammals., however more recent research suggests that scales in birds re-evolved after the evolution of feathersBird embryos begin development with smooth skin.
On the feet, the corneum, or outermost layer, of this skin may keratinize, thicken and form scales.
These scales can be organized into;  Cancella – minute scales which are really just a thickening and hardening of the skin, crisscrossed with shallow grooves.
Scutella – scales that are not quite as large as scutes, such as those found on the caudal, or hind part, of the chicken metatarsus.
Scutes – the largest scales, usually on the anterior surface of the metatarsus and dorsal surface of the toes.
The rows of scutes on the anterior of the metatarsus can be called an acrometatarsium or acrotarsium.
Reticula are located on the lateral and medial surfaces (sides) of the foot and were originally thought to be separate scales.
However histological and Evo-Devo work in this area revealed that these structures lack beta-keratin (a hallmark of reptilian scales) and are entirely composed of alpha-keratin.
This, along with their unique structure has lead to the suggestion that these are actually feather buds that were arrested early in development. 
All members of this genus are long, slightly flattened laterally and have thin bodies with large heads.
They typically have relatively large eyes, although this is less pronounced in the larger species, such as the emerald tree boa, "Corallus caninus".
The anterior teeth are highly elongated, often being several times the length one would expect for snakes of their size.
These are used for penetrating layers of feathers to get a firm grip on birds, their primary prey.
All members of the genus are nocturnal and have large numbers of very pronounced thermoreceptive pits are located between the labial scales. 
All elapids have a pair of proteroglyphous fangs used to inject venom from glands located towards the rear of the upper jaws.
In outward appearance, terrestrial elapids look similar to the Colubridae: almost all have long and slender bodies with smooth scales, a head covered with large shields and not always distinct from the neck, and eyes with round pupils.
In addition, their behavior is usually quite active, and most are oviparous.
Exceptions to all these generalizations occur: e.g.
the death adders ("Acanthophis") include short and fat, rough-scaled, very broad-headed, cat-eyed, live-bearing, sluggish ambush predators with partly fragmented head shields.
Some elapids are strongly arboreal (African "Pseudohaje" and "Dendroaspis", Australian "Hoplocephalus"), while many others are more or less specialised burrowers (e.g.
"Ogmodon", "Parapistocalamus", "Simoselaps", "Toxicocalamus", "Vermicella") in either humid or arid environments.
Some species have very generalised diets (euryophagy), but many taxa have narrow prey preferences (stenophagy) and correlated morphological specialisations, e.g.
for feeding on other snakes, elongate burrowing lizards, squamate eggs, mammals, birds, frogs, fish, etc.
Sea snakes (Hydrophiinae, sometimes considered to be a separate family) have adapted to a marine way of life in different ways and to various degrees.
All have evolved paddle-like tails for swimming and the ability to excrete salt.
Most also have laterally compressed bodies, their ventral scales are much reduced in size, their nostrils are located dorsally (no internasal scales) and they give birth to live young (ovoviviparous).
In general, they have the ability to respire through their skin; experiments with the yellow-bellied sea snake, "Pelamis platurus", have shown that this species can satisfy about 20% of its oxygen requirements in this manner, allowing for prolonged dives.
The sea kraits ("Laticauda" spp.)
are the sea snakes least adapted to aquatic life.
They spend much of their time on land, where they lay their eggs.
They have wide ventral scales, the tail is not as well-developed for swimming, and their nostrils are separated by internasal scales.