S: (n) passerine, passeriform bird (perching birds mostly small and living near the ground with feet having 4 toes arranged to allow for gripping the perch; most are songbirds; hatchlings are helpless)
S: (n) bird (warm-blooded egg-laying vertebrates characterized by feathers and forelimbs modified as wings)
S: (n) vertebrate, craniate (animals having a bony or cartilaginous skeleton with a segmented spinal column and a large brain enclosed in a skull or cranium)
S: (n) chordate (any animal of the phylum Chordata having a notochord or spinal column)