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R.A. Coon

Publications and source records attributed to R.A. Coon.

16 recordsLinked to original sources
USGS1984

Observer visitation frequency and success of mourning dove nests: A field experiment

Field studies of nesting success generally require visits by the investigator to the nests under study. Such visits may themselves influence nesting success, however, and this possibility has been discussed and investigated by a number of workers with a variety of bird species. Livezey (1980) reviewed the relevant literature for duck nests and noted that most studies failed to demonstrate differences in nesting success between visited nests and those not visited. Livezey (1980) found in his own work that nest abandonment may have occurred as a result of disturbance by observers but that nest predation was not related to time spent by observers at nests or number of observers approaching nests. Various components of nesting and breeding success in seabirds are thought to be adversely affected by human disturbance and nest visitation (Gillett et al. 1975, Robert and Ralph 1975, Ollason and Dunnet 1980). Upland, ground-nesting species have also been studied (e.g. Stoddard 1931, Evans and Wolfe 1967, Henry 1969, Roseberry and Klimstra 1970, Klimstra and Roseberry 1975), and, although conclusions have varied, a number of these workers found no effect of observers on nest-predation rates.

The Auk↗
USGS1982

Mourning Dove Nesting: Seasonal Patterns and Effects of September Hunting

A nationwide State/Federal cooperative study was initiated in 1978 to examine effects of September hunting on mourning dove (Zenaida macroura) nesting. This study was designed to (1) determine the proportion of the annual total of dove nesting activity and production that occurs in September and October, and (2) determine if survival rates of mourning dove eggs and nestlings are lower in areas where early September dove hunting is permitted compared to areas where it is prohibited. During 1979 and 1980, 6,950 active nests were followed to obtain data on nesting patterns. Nest initiation was estimated both by backdating from hatch dates and by the numbers of nests found for the first time. The nationwide percent of the annual total of nests that were initiated in September and October was 1.0% based on backdating hatch dates and 2.7% based on nests found for the first time. Nesting activity was measured by numbers of eggs and nestlings present in weekly counts. Nationally, 4.5% of the annual total of nesting activity occurred in September and October. The observed period when 80% of the nests were active, based on hatch dates, lasted from April 22 to September 4. The measure of production used in this study was numbers of young fledged. Nationally, 10.3% of all observed fledging occurred in September and October. A decline in nests found in the latter half of the nesting season preceded the September 1 start of hunting. From this we concluded that the reduction in nesting activity at the end of the season is a natural phenomenon and not caused by hunting disturbance. In a separate part of this study, we estimated survival rates in hunted and nonhunted sections from data on 668 nests. The estimated daily survival rates for individual eggs and nestlings were 95.8% in the nonhunted and 95.0% in the hunted sections; the corresponding fledging rates were 33% and 26%, respectively. The fledging rates are lower because they are the daily survival rates operating over a 26-day nesting period. Neither differences in survival nor fledging rates between nonhunted and hunted sections were found to be statistically significant (p> 0.05). We determined that the statistical test was powerful enough to detect a reduction due to hunting from a hypothetical 96.0% to 94.2% in daily nestling survival rates (from 35% to 21% fledging rates) with 80% probability. An undetected reduction in fledging rate of that magnitude would probably reduce the overall fledging rate by less than 1 percentage point, because only a small proportion of the nesting doves is exposed to hunting for the full 26 day nesting cycle. In conclusion, we found that only a small proportion of total annual nesting attempts was exposed to hunting. There was no statistically significant difference in survival rates in sections where hunting was permitted compared to sections where it was prohibited. We concluded from this study that dove hunting under current regulations has no substantial effect on recruitment of fledglings into the mourning dove population.

Book↗
USGS1982

Examination of woodcock nest sites in central Pennsylvania

Evidence is given to support Iow selectivity in choice of nest sites by woodcock (Philohela minor). Habitat characteristics measured at 30 woodcock nest sites were compared with non-nest control sites in Huntingdon County, central Pennsylvania. Mean nest density per year was 1/4.8 ha within the 54-ha study area. Of 14 characteristics measured, higher shrub-stem density at nests was the only variable significantly different (P < 0.05) from controls by univariate t-test. A multivariate t-test showed no significant difference (P > 0.05) between habitat characteristics at nests and controls. A computed discriminant function also indicated little distinction between nests and controls. Spatial distribution of nests for each of the three years did not depart significantly (P :> 0.05) from a random distribution. Although evidence is given for little overall selectivity, greater shrub-stem density at nests and associations related in part to 'edge' habitat may be important in the location of substantial numbers of woodcock nests. The mean distance from nest site to nearest tree (1.0 ? 1.1 m) and to nearest shrub (22.8 ? 17.8 cm) was significantly less (P < 0.01) than for control areas. Additional research on woodcock nest-site selection may lead to enhanced woodcock production in a variety of habitats.

Wildlife Research Report↗
USGS1981

Importance of structural stability to success of mourning dove nests

Studies of nest-site selection and nesting habitats often involve a "characterization" of nests and of habitats in which nests are found. Our objective in the present work is to identify nest-site characteristics that are associated with variation in components of Mourning Dove ( Zenaida macroura ) fitness (e.g. the probability of a nest succeeding), as opposed to simply "characterizing" dove nest sites. If certain nest- site characteristics affect the probability that a nest will succeed, then we suspect that these characteristics will be associated with either concealment (the probability of detection by certain predators) or structural stability (the probability of eggs or entire nests falling to the ground as a result of wind, rain storms, parental activity, etc.). Although other workers agree that structural stability is an important determinant of Mourning Dove nesting success (e.g. McClure 1944: 384; Woolfenden and Rohwer 1969: 59), we are aware of no actual tests of this hypothesis.

The Auk↗
USGS1977

Identification of potential harvest units in the United States of the American woodcock

Potential harvest units were examined in the United States for American woodcock (Philohela minor) based on the distribution of both direct and indirect recoveries of preseason bandings. Unweighted and weighted recoveries were used to definefour sets of units with a minimal interchange of birds. With a configuration that conforms to the existing boundary between the Atlantic and Mississippi waterfowl flyways, an average of only 3.0 percent unweighted and 4.4 percent weighted recoveries occurred outside of the respective unit. Even though another configuration showed 1.1 percent less crossover, the use of the existing flyway boundary would be more logical from a management standpoint. Identification and use of harvest units for woodcock will allow better management of the resource as regional differences in the two populations become more apparent.

Book chapter↗
USGS1976

Some characteristics of fall migration of female woodcock

Nine female woodcock ( Philohela minor ) were radio-tagged in central Pennsylvania before fall migration to monitor premigratory and migratory movements. Within 15 days of departure, 5 of the birds moved 0.8 to 8.0 km from their normally used area, but the remaining 4 did not move. In 1973 five marked woodcock began migration between 30 November and 8 December. In 1974, four birds departed between 18 and 29 November. Departures coincided with high pressure centers approaching from the north and west or low pressure centers retreating to the north and east, or both. Eight of the 9 woodcock departed 2.5 or more hours after sunset and at least 7 left before midnight. Two hatching-year birds were tracked for up to 201 km SSW of the study area during 2 nights. Their air speeds (mean + SD) were 36 + 2 and 45 + 3 km/h.

Pennsylvania↗