18 Extinct birds. Biologists at the University of California

(Riverside) are studying the patterns of extinction in the New Zealand bird population. ( Evolutionary Ecology Research , July 2003.) At the time of the Maori colonization of New Zealand (prior to European contact), the following variables were measured for each bird species:

a. Flight capability (volant or flightless)

b. Type of habitat (aquatic, ground terrestrial, or aerial terrestrial)

c. Nesting site (ground, cavity within ground, tree, cavity above ground)

d. Nest density (high or low)

e. Diet (fish, vertebrates, vegetables, or invertebrates)

f. Body mass (grams)

g. Egg length (millimeters)

h. Extinct status (extinct, absent from island, present)

Identify each variable as quantitative or qualitative.