I need a word for 'animal demography'. I would prefer it a single word but I will accept a phrase if no single-words are available.
If you consider an uncommon word, there is zoography. It has another sense also but recently, it is being used as animal demography.
n. Now rare. L16. [f. ZOO- + -GRAPHY.] Description of animals; descriptive zoology.
Latterly esp. a survey of animal populations (cf. DEMOGRAPHY). L16.
Demo (in demography) is from Greek demos "people".
Zoo (in zoography) is from Greek zoion "animal".
Demography is a standard term in ecology and evolution with regard to both animals and plants, so "Animal demography" is perfectly fine to use. Examples of use could be "demographic population model" or "the population demography of Pied flycatchers". You can also see examples by e.g. looking at text book titles at amazon. At the moment, I cannot think of a one-word substitute though.