As I understand it, the ejecta resulting from the K-T impact (also known as the end-Cretaceous or Cretaceous-Tertiary extinction event) re-entered the atmosphere all over the world; the heat from friction with the atmosphere raised the air temperature to a few hundred degrees C. All organisms all around the World were incinerated, except those that could bury underground or move into water.Now birds don't bury underground, nor do they bury their eggs. So, how come birds didn't go extinct?

To clarify, I'm not considering the longer term cooling effect (which was in turn followed by a longer term warming effect due the CO2 dumped in the atmosphere). What happened just after the impact was that a sizable fraction of the entire volume involved on the collision would be on ballistic trajectories. Most of these would fall back to Earth, while a small fraction would escape Earth's gravity. Now, these ejecta actually contain a significant fraction of the total energy of the impact and almost all of that in then dissipated as heat when they re-enter the atmosphere. This leads to shock heating of the atmosphere to at least a few hundred degrees celcius, but much higher temperatures are also possible, see also this article.

  • $\begingroup$ what is the KT impact? a meteorite? $\endgroup$ – AliceD Nov 18 '14 at 5:31
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    $\begingroup$ Are you sure about this: "raised the air temperature to a few hundred degrees C"? I'm not too into paleontology, but I admit I never heard that before. Could you please add a link to support that? $\endgroup$ – anongoodnurse Nov 18 '14 at 5:45
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    $\begingroup$ Unfortunately the premise underpinning this question is false. The Cretaceous–Paleogene extinction event did not raise temperatures (other than shortly and locally at the impact site) but rather lowered temperatures and light levels through additional particulate matter in the air. Birds survived due to being small (like mammals of the time) and thus requiring less food. Birds could also travel to where food was, as applicable. $\endgroup$ – LateralFractal Nov 18 '14 at 6:32
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    $\begingroup$ @inf3rno A faster reproduction rate would have also allowed bird species to adapt faster. Whilst non-avian dinosaurs as egg layers offloaded some of their reproductive burden, each large dinosaur still had to grow (slowly) to maturation for their next generation of reproduction. $\endgroup$ – LateralFractal Nov 18 '14 at 7:49
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    $\begingroup$ The premise 'birds do not bury themselves underground, nor do they bury their eggs' is also false. Burrow-nesting is not uncommon among modern birds, and incubating burrow-nesting birds will often spend extended periods (multiple days, sometimes weeks) attending the nest. Example: en.wikipedia.org/wiki/Wedge-tailed_shearwater $\endgroup$ – bshane Mar 9 '16 at 5:41

This article hypothesizes that the surviving avians had large and quite complex brains, giving them an advantage in finding food in the aftermath.

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