North American Crane Working Group


Date of this Version


Document Type



Gee, G.F., and G.W. Pendleton. Effects of extended photoperiod on sandhill crane reproduction. In: Wood D. A., ed. 1992. Proceedings 1988 North American Crane Workshop, Feb. 22–24, 1988. Lake Wales, Florida (Tallahassee, FL: State of Florida Game and Fresh Water Fish Commission Nongame Wildlife Program Technical Report #12, 1992), pp. 149-160.


Used by permission of the North American Crane Working Group.


Photoperiod studies were conducted with greater sandhill cranes (Grus canadensis tabida) from 1969 to 1972 and from 1982 to 1987 at the Patuxent Wildlife Research Center, Maryland. When housed indoors and exposed to long photoperiods, males produced semen during winter. When exposed to artificially extended photoperiods during spring in outdoor pens, females apparently laid earlier in the year and laid more eggs than they would have without the added light. Cranes did not exhibit any signs of photo refractory response to extended photo periods.