There are still many unsolved problems about bird life, among which are the age that birds attain, the exact time at which some birds acquire their adult dress, and the changes which occur in this with years. Little, too, is… — Paul Bartsch Copy Share Image
There are still many unsolved problems about bird life, among which are the age that birds attain, the exact time at which some birds… — Paul Bartsch Copy Share Image
Of all the ships that have been devoted to biological explorations of the sea, none has surpassed the endeavors conducted on board the U.… — Paul Bartsch Copy Share Image
