Distraction display, bill-sweeping, and nest-hole defense. Auk 85(3):477-492. Kilham, Lawrence. 1970. Feeding behavior of downy woodpeckers. I. Preference for paper birches and sexual differences. Auk 87(3):544-556. Kilham, Lawrence. 1971. Reproductive behavior of yellow-bellied sapsuckers. I. Preference for nesting in _Fomes_ infected aspens, and nest hole interrelationships with flying squirrels, raccoons, and other animals. Wilson Bull. 83:159-171. Koplin, James R. 1972. Measuring predator impact of woodpeckers on spruce beetles. J. Wildl. Manage. 36(2):308-320. Korschgen, Leroy J., and Henry S. Stuart. 1972. Twenty years of avian predator-small mammal relationships in Missouri. J. Wildl. Manage. 36(2):269-282. Laskey, Amelia R. 1940. The 1939 nesting season of bluebirds at Nashville, Tennessee. Wilson Bull. 52:183-190. Laskey, Amelia R. 1948. Some nesting data on the Carolina wren at Nashville, Tennessee. Bird-Banding 19(3):101-121. Laskey, Amelia R. 1957. Some tufted titmouse life history. Bird-Banding 28(3):135-145. Lawrence, Alexander G. 1932. New Manitoba nesting records. Free Press Evening Bull., Winnipeg. 27 May. Lawrence, Louise de K. 1949. Notes on nesting pigeon hawks at Pimisi Bay, Ontario. Wilson Bull. 61:15-25. Lawrence, Louise de K. 1967. A comparative life history of four species of woodpeckers. Ornithol. Monogr. 5:1-156. Ligon, J. David. 1967. The biology of the elf owl, _Micrathene whitneyi_. Ph.D. Diss. Michigan Univ. Ligon, J. David. 1971. Some factors influencing numbers of the red-cockaded woodpecker. P. 30-43. _In_ The ecology and management of the red-cockaded woodpecker: symposium proceedings, Okefenokee Natl. Wildl. Refuge, Folkston, Georgia, May 26-27, 1971. U.S. Dep. Int., Bur. Sport Fish. Wildl. [Published in cooperation with Tall Timbers Res. Stn., Tallahassee, Florida.] Ligon, J. David. 1973. Foraging behavior of the white-headed woodpecker in Idaho. Auk 90(4):862-869. Ligon, J. Stokley. 1961. New Mexico birds and where to find them. Univ. of New Mexico Press, Albuquerque. 360 p. Low, Seth H. 1933. Further notes on nesting of the tree swallows. Bird-Banding 4(2):76-87. Lowry, George Hines, Jr. 1960. Louisiana birds. Louisiana State Univ. Press, Baton Rouge. Mackay, Violet M., and William M. Hughes. 1963. Crested mynah in British Columbia. Can. Field Nat. 77(3):154-162. MacLellan, C. R. 1958. Role of woodpeckers in control of the codling moth in Nova Scotia. Can. Entomol. 90(1):18-22. MacLellan, C. R. 1959. Woodpeckers as predators of the codling moth in Nova Scotia. Can. Entomol. 91(11):673-680. MacRoberts, Barbara R., and M. H. MacRoberts. 1972.