Conservation and Management

Effects Of Human Activity

Hunting

Approximately 1 million U.S hunters annually harvest about 20 million birds (Dolton and Rau 2006), which represents about 7% of the fall population (Otis et al. 2008). Additional harvest occurs in Mexico and Central America (Sadler 1993) but its impacts to overall harvest are currently unknown.

Lead Pellet Ingestion And Lead Poisoning

Lead shot is ingested primarily from fields planted to attract Mourning Doves for hunting. Reported lead pellet ingestion rates for hunter-killed mourning doves vary from 0.2–6.5% depending upon locale (Conti 1993); however, these are potentially biased estimates because doves ingesting pellets may become sick relatively quickly and thus are unavailable to hunters. A few estimates of lead pellet ingestion from local sites can exceed 20% (Franson 2002). Results from laboratory studies document lead pellet ingestion rates of 5% (Schulz et al. 2007 Ingestion of 24-43 pellets has been documented in wild doves (Kendall et al. 1996, Franson 2002, Schulz et al. 2002), suggesting that Mourning Doves may ingest pellets purposefully.

Laboratory studies have shown survival rates for Mourning Doves with ≤2–19 ingested lead pellets range from 8–57% during a 21-day post-treatment period. Although some of these treatment birds survived to 21-days post-treatment, mortality risk in the wild likely would be increased from non-lethal health effects of lead poisoning (Schulz et al. 2006). A field study of wild Mourning Doves also suggests lower survival of lead-dosed birds (Carrington and Mirarchi 1989).

Pesticides And Other Contaminants/Toxics

Residues of many contaminants reported in tissues of Mourning Doves, with some resulting in fairly large die-offs (Conti 1993). From the lower Colorado River valley, studies document no-effect levels of organochlorine and of PCB residues in eggs (Garcia-Hernandez et al. 2006). No persistent concerns about population level effects.

Habitat

Mourning Doves are habitat generalists and have a positive association with both urban and rural human-altered landscapes. They make extensive use of cultivated waste grain and weed seeds in agriculture landscapes, and can establish non-migratory populations in urban and suburban areas relying on year-round bird feeding operations. Habitat management techniques such as shelterbelt establishment or manipulation of crop fields and grasslands by mowing, grazing or burning may enhance landscape productivity for Mourning Doves on a relatively local scale, but it is unlikely that large-scale habitat improvement programs could be successfully implemented or evaluated.

Human/Research Impacts

Observers may influence nesting success by pinpointing nest location to a variety of predators (Morrow and Silvy 1982). Intensive study to test hypotheses on this subject concluded predators did not respond differently to nests visited at daily or weekly intervals (Nichols et al. 1984). Prudent researchers should keep nest visitations to a predetermined minimum.

Previous Mourning Dove telemetry studies using glue-on transmitter attachment have found the technique to have relatively short term (<10 wk) reliability, and that transmitter harnesses possibly have deleterious effects. Therefore, Schulz et al. (1998) successfully developed subcutaneous transmitters with external antennas, and documented their superiority to traditional glue or harness attachment methods (Schulz et al. 2001). No negative effects of implants on body mass, heterophil:lymphocyte ratios, or fecal corticosterone levels were found in a pen study (Mong et al. 2002, Schulz et al. 2005b). Berdeen and Otis (2006) concluded that subcutaneously implanted radios did not affect survival in wild birds.

Management

Conservation Status And Harvest Management

Because the Mourning Dove is a migratory bird, authority and responsibility for its management is vested in the Secretary of the Interior. This responsibility is conferred by the Migratory Bird Treaty Act of 1918 which, as amended, implements migratory bird treaties between the U.S. and other countries. Mourning Doves are included in the treaties with Great Britain (for Canada) and Mexico. These treaties recognize sport hunting as a legitimate use of a renewable migratory bird resource (Dolton and Rau 2006). The species is considered a game bird in 38 of the 48 conterminous states. In the U.S., individual states may promulgate more restrictive regulations for hunting seasons, daily bag limits, etc., but cannot enact regulations more liberal than federal frameworks. Considered a songbird in those states where hunting is not allowed.

As suggested by analysis of band recovery data (Kiel 1959), 3 zones encompass the principal breeding, migration, and U.S. wintering areas for each population. These Units (Eastern (EMU), Central (CMU), and Western (WMU) Management Units) were established as separate management units in 1960 (Kiel 1961), and have been used since that time for harvest management decisions; Fig. 3)

Measures Proposed Or Taken

A national roadside Call Count Survey (CCS) of doves seen or heard issuing a perch coo has been conducted annually since the 1960’s. Trends derived from this survey (Dolton and Rau 2006) have been the primary basis for setting hunting regulations. In 2003, the Mourning Dove National Strategic Harvest Management Plan (Anonymous 2005) was adopted by the Flyway Councils as a strategy for improving the basis for Mourning Dove harvest management decisions. Implementation of the plan depends on harvest and population data from several new and proposed monitoring programs.

Although the federal waterfowl harvest survey had existed since 1952, the survey lacked a reliable sampling frame of names and addresses of all migratory bird hunters and, therefore, did not adequately address webless migratory game birds like Mourning Doves (Elden et al. 2002). The Migratory Bird Harvest Information Program (HIP) was developed to provide statistically reliable harvest data to guide management decisions for migratory game birds; the program became fully operational across the U.S. in 1998.

A national-scale banding program was conducted during 2003–2005 to generate data for estimating band reporting rates, harvest rates, distribution and derivation of harvest, and annual survival rates, and to provide information to guide the design on a long-term operational national banding program (Otis et al. 2008). During 2003–2005, biologists in 29 participating states banded nearly 100,000 birds, and hunters have reported almost 5,000 bands to date from harvested doves. Resultant estimated adult and juvenile harvest rates were < 10% in all management units. With the exception of a few states, mostly in the north-central U.S., at least 80% of the harvest of banded adults and juveniles occurred in the state of banding. Similarly, with only a few exceptions, nearly all recoveries in each state were derived from banded cohorts in the same state. The last national-scale dove banding study was conducted more than 30 years ago (Southeastern Association of Game and Fish Commissioners 1957, Dunks et al. 1982, Tomlinson et al. 1988, Otis 2002), and a comparison of harvest rates suggests that current harvest rate estimates for both age classes in EMU and WMU states are generally less than previous estimates, while estimates are greater or about the same in CMU states. Survival rates from the former study are significantly greater for both adults and juveniles in the EMU and the CMU (P ≤ 0.10), but no differences were found in the WMU. No important changes were found in harvest distribution or derivation patterns within the management units.

A standard technique for estimation of annual fall recruitment depends upon age-ratios of harvested birds provided by hunters in a wing collection survey. A pilot wing collection survey was established in 2005 using wings collected from hunter-killed doves from local area check-stations in 18 states (Otis and Miller 2007). In conjunction with the check-station sampling scheme, a simultaneous wing collection effort will occur using a national mail survey in 2007–2009 to compare results and estimate cost efficiency of this alternative approach for establishment of an operational monitoring program for recruitment.

Use of lead ammunition for hunting is a challenging management and policy issue for conservation organizations. The 1991 nationwide ban on lead shot for waterfowl hunting resulted after an extended dialogue among many constituencies that represented scientific, environmental, recreational, social, and political viewpoints. A 2006 survey reported that 38% of states required use of nontoxic shot for dove hunting on some portion of their public lands (Case 2006), and there is active dialogue among similar stakeholders about the merits of a nationwide ban on lead shot.

Feeding fields are managed in many regions to attract doves, primarily for hunting purposes (Baskett 1993, Schulz et al. 2003), but no large-scale Mourning Dove habitat management programs have been implemented.

Evaluation Of Harvest Management

The relationships between harvest regulations, realized harvest, and population vital rates remain uncertain owing to the lack of designed studies and long-term monitoring programs. A study in the EMU that experimentally increased bag limits to improve understanding of the relationship between annual survival and harvest rates failed to significantly increase harvest rates, and thus no changes in annual survival rates could be detected (Hayne 1975, Otis and White 2002). Harvest regulations in the WMU were restricted in 1987 because of a long-term decreasing CCS trend, and the trend has since stabilized, but there are no available data for rigorously evaluating the role of hunting versus other potential causative factors (Anonymous 2005).

Management Needs

Earlier reviews of management needs (Braun et al. 1993, Tomlinson et al. 1994) emphasized the importance of operational monitoring programs that inform improved harvest management strategies. Much progress has been made toward this goal, but challenges remain (Anonymous 2005). Programs designed to maintain recreational sport hunting as an important cultural activity during the next century must be innovative, and cognizant of current societal and cultural changes, as well as the expanding urban and suburban sectors of the U.S. population (Schulz et al. 2003). Programs and activities in support of increased hunting opportunity should target public lands near urban centers (Cordell and Super 2000). Natural resource agencies and conservation organizations should support web-accessible extension publications that promote understanding of Mourning Dove biology and provide information for habitat enhancement in urban and rural landscapes (Anonymous 2006)