Captive Doves Research Articles

Avoidance of neonicotinoid-treated seeds and cotyledons by captive eared doves (Zenaida auriculata, Columbidae)

Farmland birds can be exposed to neonicotinoids through the ingestion of treated unburied seeds and cotyledons. The aim of this study was to evaluate the avoidance of sorghum with imidacloprid, clothianidin or thiamethoxam, soybean with imidacloprid, and soybean cotyledons with imidacloprid or thiamethoxam on eared doves (Zenaida auriculata). Doves were fed with test food (untreated and neonicotinoid-treated sorghum, soybean or soybean cotyledons) and maintenance food (seed mix) for 3–5 days to study the repellency (primary repellency and conditioned aversion) and anorexia caused by neonicotinoid-treated food, followed by a 7-day period on maintenance food to study the persistence of the anorexic effect after neonicotinoid exposure. Immediately afterward, the same doves were exposed to treated test food during a second period of 3–5 days to study the potential reinforcement of food avoidance. Finally, doves were fed with untreated test food to test the capacity of the pesticide to induce conditioned food aversion against untreated food in subsequent encounters. Intoxication signs and differences of body weight were determined. With sorghum, the three neonicotinoids produced a decrease in the consumption of treated seeds by >97% compared to control birds. However, this was not enough to prevent the death of 3/8 and 1/8 of the doves exposed to imidacloprid and clothianidin, respectively. Anorexia was clearly observed with neonicotinoid-treated sorghum. The birds did not avoid the untreated sorghum after exposure to the treated sorghum, indicating that avoidance is not generalized to the type of food without an associated sensory cue. The results obtained with soybean seeds and cotyledons were less conclusive because captive doves hardly consumed these foods, even without neonicotinoid treatment. The avoidance of sorghum seeds treated with neonicotinoids was insufficient to prevent poisoning and death of eared doves.

Revisiting the importance of accounting for seasonal and diel rhythms in fecal stress hormone studies

Measurement of fecal glucocorticoid metabolites (FGMs) has been used to quantify stress responses by a wide variety of species; yet, few studies attempt to conduct baseline research prior to investigating effects of disturbances on FGM levels. We evaluated the potential confounding effect of seasonal and diel rhythms on the interpretation of FGM values, by studying long-term patterns of FGMs in white-tailed deer (Odocoileus virginianus) and mourning doves (Zenaida macroura) between 2001 and 2002 in a controlled environment at facilities located at the Charles W. Green Conservation Area, near Ashland, Missouri, USA. For 1 year, we collected fresh fecal samples (<1 hr old) on a weekly basis from 17 captive deer and 8 captive doves. We also conducted hourly sampling over discrete 48-hour periods to evaluate diel rhythms. In deer, we observed that FGMs were nearly 2 times higher during spring months of April and May compared with late winter (i.e., Jan and Feb) and late summer (i.e., Jul and Aug). Dove FGMs were 50% higher during the late spring (i.e., May and Jun) compared with early spring and winter months (Jan–Apr), and twice as high as during late summer, autumn, and early winter months of August through December. In both species, we observed considerable variation in diel rhythms that was inconsistent across individuals. Collectively, our findings emphasize the need for researchers to design sampling schemes that account for high levels of individual and temporal variability in baseline FGMs—and consistently ask: What are “normal” FGM values in the context of the animal's environment and prevailing stressors. © 2015 The Wildlife Society.

Competition promotes the evolution of host generalists in obligate parasites.

Ecological theory traditionally predicts that interspecific competition selects for an increase in ecological specialization. Specialization, in turn, is often thought to be an evolutionary 'dead end,' with specialist lineages unlikely to evolve into generalist lineages. In host-parasite systems, this specialization can take the form of host specificity, with more specialized parasites using fewer hosts. We tested the hypothesis that specialists are evolutionarily more derived, and whether competition favours specialization, using the ectoparasitic feather lice of doves. Phylogenetic analyses revealed that complete host specificity is actually the ancestral condition, with generalists repeatedly evolving from specialist ancestors. These multiple origins of generalists are correlated with the presence of potentially competing species of the same genus. A competition experiment with captive doves and lice confirmed that congeneric species of lice do, in fact, have the potential to compete in ecological time. Taken together, these results suggest that interspecific competition can favour the evolution of host generalists, not specialists, over macroevolutionary time.

Importance of Native Seeds in White‐Winged Dove Diets Dominated by Agricultural Grains

ABSTRACT Agricultural intensification is a key factor in the decline of many avian populations throughout the world, yet the exact mechanisms that contribute to these declines are relatively unresolved, especially for seed‐eating species. We tested the hypothesis that forage quality, particularly protein content, limits productivity in birds consuming diets dominated by agricultural grains and lacking in native forages. We used white‐winged doves (Zenaida asiatica) because columbids are highly granivorous and white‐winged doves have declined in areas dominated by grain agriculture. We randomly assigned 52 pairs of captive doves to 1 of 2 treatments: we fed one treatment sorghum (Sorghum bicolor) and the second sorghum plus native seeds (croton [Croton sp.] and native sunflower [Helianthus sp.]). Birds with access to native seeds fledged 123% more young per pair, with young weighing 32% more at fledging than those fed only sorghum. Doves with access to native seeds selected a diet consisting of 43% sorghum, 32% croton, and 25% sunflower. We conclude that agricultural grains, which typically have high metabolizable energy and low to moderate protein concentrations, are not sufficient for normal productivity of white‐winged doves. The lack of native forages with sufficient metabolizable energy and protein content may be a factor in the declining productivity of white‐winged doves in the lower Rio Grande Valley of Texas, USA, as well as other species in regions dominated by agriculture.

Mourning Doves and Salt: Is There an Attraction?

Baiting with sodium salt (hereafter salt) to attract mourning doves (Zenaida macroura) for hunting has been illegal since 1931, yet no comprehensive study of the relationship between mourning doves and salt in the environment has been conducted. We measured consumption of freely available salt by captive male and female mourning doves, and we tested effects of season, grit availability, and reproductive status on salt consumption. Additionally, we evaluated the attraction of wild mourning doves to salt by comparing dove use among resource patches containing food and salt baits, salt bait, food bait, and no bait at 2 sites in eastcentral Alabama. Captive doves consumed 20 + 3 (x t SE) mg salt/day. Salt consumption did not vary between genders, among seasons, or with availability of another grit source. Grit consumption by females during April-May was greater than during other periods, and greater than consumption by males during any period. Pairs of doves successfully hatching young consumed more salt/dove/day than did unsuccessful pairs or unpaired doves. Among successful nesters, mean salt consumption was highest during the week following hatching. Wild mourning dove use was similar between patches containing both food and salt and those containing food, and between patches containing salt and unbaited patches. Results confirm that mourning doves will consume salt in their environment, particularly during nesting, apparently in response to physiological demand for sodium. However, salt did not appear to attract wild mourning doves, perhaps due to physiological sodium-conserving mechanisms or the availability of natural sodium sources. Salt does not appear to function as grit in the diet of mourning doves. Grit may be an important source of calcium for doves during reproduction. Regulations prohibiting salt baiting for dove hunting may not be necessary, although additional research should be conducted in other areas to test our results. JOURNAL OF WILDLIFE MANAGEMENT 66(2):425-432

Molt of After-Hatching-Year Mourning Doves

We studied molts and plumages of 28 captive and 112 wild after-hatching-year (AHY) mourning doves (Zenaida macroura) in eastcentral Alabama to better understand the timing of, processes involved in, and factors affecting annual molt Captive doves were paired and reproduced in outdoor flight pens exposed to natural photoperiod and weather. We evaluated molt progression in captive doves at 28-day intervals. During the weeks we examined captive doves, we also trapped and evaluated molt in wild doves For captive and wild doves, time (sampling period) was the only consistent factor affecting inolt (P < 0.001). Body molt of captive and wild doves began in August, peaked in October, and ended by December Tail feather (rectrix) molt coincided with body molt in captive but not wild doves. Molt of primary feathers (remiges) in both groups followed an orderly outward sequence and was initiated by May and completed by December. The complete body molt initiated in late summer resulted in the drab plumage typical of mourning doves in winter. Males had visible olive-colored tips on the crown, hind neck, and, to a lesser degree, the chest. Gradual deterioration of the margins of these feathers revealed the more colorfnl breeding plumage by late winter and early spring Although the winter plumage of females also was olive-tipped it did not contrast enough with the spring plumage to cause a noticeable seasonal color change. Apparently, AHY mourning doves compensate for molt-breeding overiap by spreading wing molt over ≥6 months by initiating annual body head and tail molt when food is abundant in autumn, and by timing the majority of molt concurrent with, or following, the final clutch of the season, just prior to the stressors of winter.

Ventilated Capsule Measurements of Cutaneous Evaporation in Mourning Doves

To determine the contribution of cutaneous water loss to evaporative cooling in Mourning Doves (Zenaida macroura), we used a ventilated capsule technique to measure evaporation from the breast, back, and axilla of captive doves at 25 and 350C. Water loss from these surfaces averaged 4.1 ? 0.4 mg m-2 sec-' (SE) at 250C and was highest from the dorsum. At 350C, cutaneous evaporation increased to 8.3 ? 0.9 mg m-2 sec-'. Mean skin water-vapor diffusion resistance of the breast, back, and axilla together was 111.5 ? 9.5 sec/cm at 250C and decreased significantly to 69 ? 8.0 sec/cm at 350C. The large increases in cutaneous evaporation we observed between 25 and 350C result mainly from temperaturedependent reductions in the skin resistance to water loss. Our results suggest that augmented cutaneous evaporation is utilized as a means of heat defense by Mourning Doves.