--- title: Birds: feathers, wings, eggs and flight — a lesson of Mova's school · trees and pragmatics description: «Birds: feathers, wings, eggs and flight», a lesson of the biology course of Mova's primary school, sentence by sentence with dependency trees and pragmatics. It begins: Birds are the only animals alive today with feathers, and nearly every part of a bird is built to be light and strong for flying. --- [Mova](https://md.mova.elamur.ai/free/en/) · [this page in HTML](https://mova.elamur.ai/free/en/corpora/school/biology/33-birds-feathers-wings-eggs-and-flight/) [home](https://md.mova.elamur.ai/free/en/) / [corpora](https://md.mova.elamur.ai/free/en/corpora/) / [school](https://md.mova.elamur.ai/free/en/corpora/school/) / [Biology](https://md.mova.elamur.ai/free/en/corpora/school/biology/) / Birds: feathers, wings, eggs and flight # Birds: feathers, wings, eggs and flight Lesson 33 of the biology course of Mova's primary school: 16 sentences, each with its syntax tree and pragmatics. The lessons are written for Mova, and their agreed trees are part of Mova corpus 0.4 (CC BY-SA 4.0). How Mova does on its tests: [the lesson at school](https://md.mova.elamur.ai/free/en/school-run/biology/33-birds-feathers-wings-eggs-and-flight/). - [0](https://md.mova.elamur.ai/free/en/corpora/school/biology/33-birds-feathers-wings-eggs-and-flight/0/) — Birds are the only animals alive today with feathers, and nearly every part of a bird is built to be light and strong for flying. - [1](https://md.mova.elamur.ai/free/en/corpora/school/biology/33-birds-feathers-wings-eggs-and-flight/1/) — Put a pigeon feather under a magnifying glass: a shaft in the middle, hundreds of branches called barbs, and on them tiny barbules with hooks that zip together like Velcro. - [2](https://md.mova.elamur.ai/free/en/corpora/school/biology/33-birds-feathers-wings-eggs-and-flight/2/) — Snap a chicken bone from Sunday dinner and it is hollow, with thin struts inside like a bridge, light but strong. - [3](https://md.mova.elamur.ai/free/en/corpora/school/biology/33-birds-feathers-wings-eggs-and-flight/3/) — Birds are living dinosaurs: a chicken's scaly foot with three forward toes looks just like a dinosaur's in the museum because it was inherited from them. - [4](https://md.mova.elamur.ai/free/en/corpora/school/biology/33-birds-feathers-wings-eggs-and-flight/4/) — They have no teeth, so a hen swallows little pebbles that grind food in a muscly gizzard, and that white splat on the car is not poo at all but the bird's version of wee. - [5](https://md.mova.elamur.ai/free/en/corpora/school/biology/33-birds-feathers-wings-eggs-and-flight/5/) — A feather has a central shaft with barbs, and each barb has tiny barbules with hooks that zip together like Velcro; birds re-zip them by preening. - [6](https://md.mova.elamur.ai/free/en/corpora/school/biology/33-birds-feathers-wings-eggs-and-flight/6/) — Many bird bones are hollow, with thin crossing struts, and some are filled with air connected to the lungs. - [7](https://md.mova.elamur.ai/free/en/corpora/school/biology/33-birds-feathers-wings-eggs-and-flight/7/) — Birds make no runny urine: their waste comes out as a white paste of uric acid, together with dark poo, from the same opening. - [8](https://md.mova.elamur.ai/free/en/corpora/school/biology/33-birds-feathers-wings-eggs-and-flight/8/) — An egg has an air pocket at the wide end, white for water and cushioning, a yolk for food, and thousands of tiny holes in the shell that let air in; before it breaks the shell the chick takes its first breaths from the air pocket. - [9](https://md.mova.elamur.ai/free/en/corpora/school/biology/33-birds-feathers-wings-eggs-and-flight/9/) — Supermarket eggs never hatch because the hens live without a cockerel, and a hen lays about one egg a day. - [10](https://md.mova.elamur.ai/free/en/corpora/school/biology/33-birds-feathers-wings-eggs-and-flight/10/) — A chick breaks out using an egg tooth, a hard point on its beak that falls off a few days after hatching; people should not help it out, because it is still taking in the last of its yolk and will finish by itself. - [12](https://md.mova.elamur.ai/free/en/corpora/school/biology/33-birds-feathers-wings-eggs-and-flight/12/) — Ducks spread oil from a gland near the tail over their tightly zipped feathers, so rain runs off them; thick oil from a spill at sea glues the feathers so water gets in and the bird gets soaked and cold. - [13](https://md.mova.elamur.ai/free/en/corpora/school/biology/33-birds-feathers-wings-eggs-and-flight/13/) — Geese fly in a V because each bird rides the rising air from the wingtip of the bird in front, saving energy; they take turns at the front. - [14](https://md.mova.elamur.ai/free/en/corpora/school/biology/33-birds-feathers-wings-eggs-and-flight/14/) — Swallows from Britain fly about 10,000 km to South Africa for the winter, because a British winter has almost no flying insects for them to eat, and South Africa has plenty. - [15](https://md.mova.elamur.ai/free/en/corpora/school/biology/33-birds-feathers-wings-eggs-and-flight/15/) — When a perching bird bends its legs, tendons pull its toes tight round the branch, so it can sleep without falling off. - [16](https://md.mova.elamur.ai/free/en/corpora/school/biology/33-birds-feathers-wings-eggs-and-flight/16/) — Birds have no teeth; swallowed grit in a muscly stomach called the gizzard grinds the food, and having no heavy jaws full of teeth keeps the head light for flying. - ← previous: [Frogs, toads, newts and salamanders](https://md.mova.elamur.ai/free/en/corpora/school/biology/32-frogs-toads-newts-and-salamanders/) - next →: [Birds of prey and owls](https://md.mova.elamur.ai/free/en/corpora/school/biology/34-birds-of-prey-and-owls/) - ↑ back to [Biology](https://md.mova.elamur.ai/free/en/corpora/school/biology/)