The significance of crop-gland activity in mourning doves during the hunting season in Virginia

Two investigations were conducted: (1) a study of the proportion of mourning doves (Zenaidura macroura) shot during the hunting season in Virginia which had evidence of crop-milk production activity, and (2) an investigation of the persistence of crop-gland activity following its induction by exogenous prolactin.

Mourning doves shot during the 1971 and 1972 hunting seasons at Elm Hill Wildlife Management Area, Mecklenburg County, Virginia were examined for crop-gland and gonad activity. Examination dates (numbers of adult doves in parentheses) were as follows: September 4, 1971 (82); September 2, 1972 (279); September 9, 1972 (89); September 16, 1972 (34); September 23, 1972 (14); and December 23, 1972 (11). The proportion of doves with active crops on the respective examination dates were as follows: 12.5 percent, 22.6 percent, 23.6 percent, 29.3 percent and nil, respectively, on the above dates. Female doves with eggs in the oviduct represented 4.3 percent of those examined on September 4, 1971 and 5.8 percent of those examined on September 2, 1972. The results indicated that a substantial proportion of doves were engaged in nesting activity during the hunting season. Results of investigations of persistence of crop-milk production activity in pigeons (Columba livia) following prolactin injection indicate rapid regression of anatomical changes in the crop-gland following cessation of the injections.