The Life of Birds — S01E08 — The Demands of the Egg

00:00:45 These sooty terns are amongst the most aerial of birds.

00:02:00 so they are equally spaced with almost mathematical precision.

00:03:57 The nests of palm swifts are minimal, but they put them in fairly inaccessible places,

00:05:58 But this is not a safe enough place for their precious eggs.

00:08:15 so each hole, when it is finished, is a valuable property,

00:09:57 Perhaps this one will do.

00:11:25 They build their nests. And builders, of course, need building materials.

00:14:34 Tree swallows compete with one another in collecting them.

00:17:48 And this, in one that has flaky bark.

00:19:51 Some birds build nests not just as cradles for their eggs and chicks,

00:21:08 During the day it gets ferociously hot,

00:23:16 Each egg, emerging from one as a microscopic cell,

00:25:08 If they do that, they must lay it in a nest that is really secure,

00:26:57 But the red-breasted toucan has a long beak.

00:29:45 But in fact this part of the nest has never had any eggs in it.

00:32:27 And now she starts a most bizarre pantomime.

00:34:43 The birds are accurate judges of temperature. They have to be.

00:36:23 so her mate looks after her, and he will have to do this for almost two months.

00:38:29 Perhaps she can try the same trick.

00:41:09 but there is still a chance that one or two of this female's eggs laid elsewhere will survive.

00:42:36 It has put an egg in the nest of a gnatcatcher.

00:44:32 And the weavers seem well aware of the danger.

00:46:38 The colors of their eggs are extraordinarily variable,

00:48:14 is what we will be looking at in the next programme in The Life of Birds.