SUMMER ABOVEGROUND MOVEMENTS OF NORTHERN POCKET GOPHERS, THOMOMYS-TALPOIDES, IN AN ALFALFA FIELD

Northern Pocket Gophers' (Thomomys talpoides) above-ground movements w ere studied with a fluorescent U.V, powder spread over 10 to 18 burrow systems from 1 June to 8 September 1993 in an alfalfa field near Vegr eville, Alberta. Gophers did not limit their surface activities to bur row openings. The number of burrow systems with above-ground movements over a 48-h period decreased from June (90%) to July (50%), August (1 7%), and September (OB). Gophers exiting their burrow system produced trails with an average length of 28.7 (SE = 2.4) cm in June, 16.8 (+/- 4.1) cm in July, and 23.0 (+/- 5.7) cm in August. The mean sums of tr ail lengths per burrow system were significantly greater (P < 0.05) in June (130.8 +/- 32.6 cm) than in July (43.6 +/- 16.5 cm) and August ( 46.0 +/- 12.0 cm). In late summer, surface movements were almost nonex istent. The number and extent of gophers' above-ground movements may b e related to the presence of vegetative cover and a gradual change in feeding behavior over summer.