Do the Evolution
This avian foot morphology is the same one that Velociraptor used to run down prey
Anisodactyl
Flight depends on this large morphological structure of birds, which James Patterson clearly forgot about.
Keeled Sternum
Monotremes
Birds are mostly bad at this, but it is the primary sense of mammals.
Smell
The sale of bison tongues, whooping crane feathers, and the trade of wild-caught parrots are all examples of this phenomenon that can reduce populations.
Overexploitation.
Therapsids outcompeted this reptile ancestor with a huge dorsal "fin" and a name that has nothing do do with the fish-gulping bird.
Pelycosaurs
Given their name, it is odd that only 50% of this group has this structure.
Marsupium or Pouch.
This morphological structure in birds is the equivalent of mammalian teeth.
Gizzard
Experiments in a planetarium showed that birds were using this to help them navigate at night.
Star Map
One of the biggest conservation issues facing birds and mammals is the continued destruction, fragmentation, and destruction of this basic necessity for populations.
Habitat
These two mammal groups are most closely related to each other, in part because they share a common reproductive structure.
Placentals and Marsupials
Although some mammals lack it, this structure likely allowed it's namesake group to outcompete the others and dominate the planet.
Placenta.
Many birds and some mammals use this same strategy to deal with winter conditions.
Migration
This functional group goes against the sensory norm for mammals, although maybe less than we initially thought.
Primates.
Ealgles, osprey, and other fish-eating birds where hit hard by this chemical, which Rachel Carson helped to ban.
DDT
Birds and theropod dinosaurs share many characteristics, including this type of neck.
S-shaped
These teeth are used by mammals to tear flesh, which makes sense for their functional group.
Carnassials
Ducks, wild turkeys, and deer all produce offspring of this type, perhaps for the same ecological reasons.
Precocial
Many mammals have the equivalent of bird bristles, used to help them find food or navigate tight spaces.
Whiskers.
This disease affects flying organisms, but only the one that hibernates in caves.
White Nose Syndrome
Surface Area and Volume
This part of a feather was likely used to sign the Declaration of Independence, the Constitution, and the Bill of Rights, among other things.
Calamus.
True (flapping) flight evolved this many times among vertebrates, although in very different ways.
Three
Mammals usually have more of this sort of cell within their eyes, which belies our nocturnal evolution.
Rods
This flightless parrot is endangered because of invasive mammals, none of which are hobbits.
Kakapo