Reproductive ecology of the mourning dove: large-scale patterns in recruitment, breeding endocrinology, and developmental plasticity
This dissertation examines multiple aspects of the reproductive ecology of mourning doves (Zenaida macroura). The work builds on a long tradition of research on their reproductive ecology (McClure 1943, Hanson and Kossack 1963), techniques for large-scale monitoring of reproduction (Ruos and Tomlinson 1967), and endocrinology of Columbids (Riddle 1933). I have expanded this body of knowledge in a way that hopefully will make worthwhile contributions to knowledge of 1) techniques for monitoring reproduction, 2) geographic and weather related variation in annual recruitment, 3) endocrinology during breeding, and 4) the role of developmental plasticity in response to stress early in life.
The mourning dove is an important migratory game bird in the United States where more than 20 million birds are harvested annually. Its importance as a game species has been the impetus for a coordinated effort by state and federal agencies to improve harvest management for the species. A national strategic harvest management plan has been developed that emphasizes the use of population models to develop an informed long-term strategy for harvest (Anonymous 2004). Establishing monitoring programs for population vital rates is a critical component of the plan and priorities include instituting a large-scale operational program for monitoring reproductive rates. Large-scale studies for mourning doves between the 1950's and 1980's determined migration patterns (Kiel 1959), survival and harvest rates (Hayne 1975, Dunks et al. 1982, Tomlinson et al. 1988), and recruitment rates (Ruos and Tomlinson 1967, Geissler et al 1987). However, more recent monitoring of mourning dove populations has been based solely on the Call Count Survey, an annual roadside index to dove abundance (Anonymous 2004), until a large-scale banding effort was resumed in 2003 (Otis et al. 2008). A program to monitor recruitment rate will be an important complement to banding to generate estimates of population vital rates.
In 2005, with the cooperation of 22 state agencies and US Fish and Wildlife Service personnel and funding from the Webless Migratory Gamebird Research Grant program, I organized a pilot harvest parts collection program aimed at developing a national program for monitoring dove recruitment rates. I used wings collected from this program during 2005-2008, in addition to wings collected in parallel as part of a national mail survey by the US Fish and Wildlife Service in 2007 and 2008, in analyses in Chapter 2 and 3, which make up the first section of my dissertation. I developed statistical techniques to calibrate age ratios from collected wings and to estimate population age ratios (Chapter 2 - Calibrating recruitment estimates for mourning doves from harvest age ratios). I also use these data to determine how reproduction varies geographically and how annual variation correlates with variation in weather (Chapter 3 - Range-wide estimates of mourning dove recruitment and their relationship to annual weather variation). These chapters serve as a basis for the development of a long-term operational program for monitoring mourning dove recruitment.
In addition to work on large-scale monitoring of recruitment, during the summers of 2005-2007, I initiated work with local breeding doves in central Iowa. Mourning doves offer an ideal model to examine hypotheses about parental effects and developmental plasticity as they relate to the growth and development of young. Mourning doves have an extended range both in geographical extent and across a range of habitats (McClure 1943, Hanson and Kossack 1963, Otis et al. 2008). They have a determinant clutch size of 2 eggs and one of the most protracted nesting seasons among North American birds, during which multiple nesting attempts occur. In my study areas in central Iowa during 2005-2007, nest initiations range from Mar 20 to Sept 15. Plasticity in parental effects and in growth and development of young are likely to be important for successfully breeding across the wide gradient of environmental conditions within their breeding range to which they are exposed. The work on breeding ecology presented in my dissertation is focused on two areas. First, I examined the relationship of prolactin and corticosterone levels, two important hormones affecting behavior during reproduction, to parental effort during the nestling period (Chapter 4 - Individual variation in baseline and stress-induced corticosterone and prolactin levels predicts parental effort by nesting mourning doves). Second, I examined patterns in growth and development as they related to developmental stress with a particular emphasis on the role of plasticity in affecting flight ability of juvenile doves. I focused on fledging ability, which initiates an important life history transition from nestling to fledgling stages for doves (Chapter 5 - Morphological plasticity reduces the effect of poor developmental conditions on fledging age in mourning doves) and on take-off speed as well as growth in weight and size during the post-fledging period up to 90 d of age (Chapter 6 - Immediate versus delayed effects of early nutritional stress on growth and flight ability of juvenile mourning doves).
Anonymous. 2004. Mourning dove national strategic harvest management plan. National Mourning Dove Planning Committee. 12pp.
Dunks, J.H., R.E. Tomlinson, H.M. Reeves, D.D. Dolton, C.E. Braun, and T.P. Zapatka. 1982. Migration, harvest, and population dynamics of mourning doves banded in the central management unit, 1967-1977. U.S. Fish and Wildlife Service Special - Scientific Report - Wildlife 249.
Geissler, P.H., D.D. Dolton, R. Field, R.A. Coon, H.F. Percival, D.W. Hayne, L.D. Soileau, R.R. George, J.H. Dunks and S.D. Bunnell. 1987. Mourning dove nesting: seasonal patterns and effects of September hunting. U.S. Fish and Wildlife Resource Publication 168.
Hanson, H.C. and C.W. Kossack. 1963. The mourning dove in Illinois. Technical Bulletin 2. Illinois Department of Conservation, Illinois.
Hayne, D.W. 1975. Experimental increase of mourning dove bag limit in eastern management unit. Southeastern Association of Game and Fish Commissioners Technical Bulletin 2.
Kiel, W.H. 1959. Mourning dove management units - a progress report. Special Scientific Reports - Wildlife No. 42. U.S. Fish and Wildlife Service, Washington, D.C.
McClure, H.E. 1943. Ecology and management of the mourning dove, Zenaida macroura (Linn.), in Cass County, IA. Iowa Experimental Station Research Bulletin 310:355-415.
Otis, D.L., J.H. Schulz, D.A. Miller, R.E. Mirarchi, and T. S. Baskett. 2008. Mourning Dove (Zenaida macroura), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology.
Otis, D.L., J.H. Schulz, and D.P. Scott. 2008. Mourning dove (Zenaida macroura) harvest and population parameters derived from a national banding study. U.S. U.S. Department of Interior, Fish and Wildlife Service, Biological Technical Publication FWS/BTP‐R3010‐2008, Washington D.C.
Riddle, O., R.W. Bates and S.W. Dykshorn. 1933. The preparation, identification and assay of prolactin - a hormone of the anterior pituitary. American Journal of Physiology 105:191:215.
Ruos, J.L. and R.E. Tomlinson. 1967. Results of mourning dove wing collection in the eastern management unit, 1966-67. U.S. Bureau of Sport Fisheries and Wildlife Administration Report.
Tomlinson, R.E., D.D. Dolton, H.M. Reeves, J.D. Nichols, and L.A. McKibben. 1988. Migration, harvest, and population characteristics of mourning doves banded in the western management unit, 1964-1977. U.S. Fish and Wildlife Service - Fish and Wildlife Technical Report 13.