Brood-rearing Season Research Articles

High-Frequency Photographic Imaging Provides Novel Insights into Nesting Bald Eagle Diet and Opportunities for Public Engagement

Bald eagles (Haliaeetus leucocephalus) were formerly endangered in the contiguous United States, but have since recolonized much of their past range. Maintaining bald eagle populations following recovery requires knowledge of factors that influence nesting success, including food habits during the brood-rearing period. We examined over 26,000 images from a high-resolution, above-nest digital camera to document the diet of a nesting bald eagle pair in north-central Indiana, U.S.A., during the 2018 brood-rearing period. After the hatch of two eaglets in April 2018, the camera was programmed to take still photos of the nest every 20 min, in addition to live-streaming video to YouTube for public audiences. Still images were used to quantify and identify all prey deliveries to the lowest taxonomic level possible, typically species. A total of 135 prey items and at least 26 prey taxa were recorded during the 75 d of the study, although daily prey count became uncertain in the final 20 d as fledglings began to move out of camera view. The majority of recorded prey items (73%) were fish, with redhorse suckers (Moxostoma spp.) representing the most numerous of the 13 fish taxa observed. Smaller numbers of birds (13%), mammals (10%), and reptiles (4%) were also observed. Although our results represent one nest across a single brood-rearing season, we gained novel insights through the analysis of high-frequency, high-definition images that provided increased temporal and taxonomic resolution of prey deliveries. The use of a camera not only avoided historical biases in bald eagle diet analysis, but also provided a valuable tool to engage public audiences.

Ecological correlates of fecal corticosterone metabolites in female Greater Sage-Grouse (Centrocercus urophasianus)

Measurement of physiological responses can reveal effects of ecological conditions on an animal and correlate with demographic parameters. Ecological conditions for many animal species have deteriorated as a function of invasive plants and habitat fragmentation. Expansion of juniper (genus Juniperus L.) trees and invasion of annual grasses into sagebrush (genus Artemisia L.) ecosystems have contributed to habitat degradation for Greater Sage-Grouse (Centrocercus urophasianus (Bonaparte, 1827); hereinafter Sage-Grouse), a species of conservation concern throughout its range. We evaluated relationships between habitat use in a landscape modified by juniper expansion and annual grasses and corticosterone metabolite levels (stress responses) in feces (FCORTm) of female Sage-Grouse. We used remotely sensed data to estimate vegetation cover within the home ranges of hens and accounted for factors that influence FCORTm in other vertebrates, such as age and weather. We collected 35 fecal samples from 22 radio-collared hens during the 2017–2018 brood-rearing season (24 May–26 July) in southwestern Idaho (USA). Concentrations of corticosterone increased with home range size but decreased with reproductive effort and temperature. The importance of home range size suggests that maintaining or improving habitats that promote smaller home ranges would likely facilitate a lower stress response by hens, which should benefit Sage-Grouse survival and reproduction.

Are Lek Disturbance Buffers Equitable for All Gunnison Sage-Grouse Populations?

Abstract Lek disturbance buffers can be used to identify areas that provide important seasonal habitat for Gunnison sage grouse Centrocercus minimus (hereafter GUSG), a species with declining or vulnerable populations across their range. Lek disturbance buffers define areas around leks where anthropogenic disturbance is not permitted and have been considered for potential conservation strategies across GUSG habitat. Currently there is minimal information available on the effectiveness of the size of defined lek disturbance buffers. This study focused on two GUSG populations, the smaller Crawford population and a segment of the larger Gunnison Basin population. We utilized global positioning system location data on GUSG to evaluate seasonal use within three lek disturbance buffers, then compared and contrasted results between the two populations. The Crawford GUSG population showed increased movements from breeding season to late brood-rearing season and in winter returned to a usage pattern similar to the breeding season. Comparatively, the western Gunnison Basin GUSG population showed considerable movement throughout the entire year. In addition to these differences, we noted remarkable differences in distance between active leks, home range size, and total daily distance traveled between Crawford and western Gunnison Basin populations. Lek disturbance buffers created using the standard protocol provided varying protection depending on the distance between leks and number of leks. In small populations, the disturbance buffers overlapped each other, thus producing a smaller total lek disturbance buffer area. In addition to adding to the general body of knowledge of a little-studied species, our study had two important findings: 1) the use of empirical cumulative distribution demonstrated considerable differences in lek disturbance buffer use between the Crawford and the western Gunnison Basin populations, and 2) lek disturbance buffers did not provide equal protection for all populations on the basis of their current definition and derivation. We anticipate that land managers will find our results useful and informative when developing land management plans for the conservation of GUSG. Our analysis showed that the variability between populations and species is important for managers to consider when developing conservation strategies, especially for small populations.

A DNA barcoding method for identifying and quantifying the composition of pollen species collected by European honeybees, Apis mellifera (Hymenoptera: Apidae)

The European honeybee, Apis mellifera L. (Hymenoptera: Apidae), is the most important crop pollinator, and there is an urgent need for a sustained supply of honeybee colonies. Understanding the availability of pollen resources around apiaries throughout the brood-rearing season is crucial to increasing the number of colonies. However, detailed information on the floral resources used by honeybees is limited due to a scarcity of efficient methods for identifying pollen species composition. Therefore, we developed a DNA barcoding method for identifying the species of each pollen pellet and for quantifying the species composition by summing the weights of the pellets for each species. To establish the molecular biological protocol, we analyzed 1008 pellets collected between late July and early September 2016 from five hives placed in a forest/agricultural landscape of Hokkaido, northern Japan. Pollen was classified into 31 plant taxa, of which 29 were identified with satisfactory discrimination (25 species and 4 genera) using trnL-trnF and ITS2 as DNA barcoding regions together with available floral and phenological information. The remaining two taxa were classified to the species level using other DNA barcoding regions. Of the 1008 pollen pellets tested, 1005 (99.7%) were successfully identified. As an example of the use of this method, we demonstrated the change in species composition of pollen pellets collected each week for 9 weeks from the same hive.

Interior Least Tern Productivity in Relation to Flow in the Central Platte River Valley

Implementation of the Platte River Recovery Implementation Program's adaptive management plan has proceeded with the understanding that management uncertainties, expressed as hypotheses, encompass complex physical and ecological responses. Adaptive management in the Platte River ecosystem relies on a combination of monitoring of physical and biological responses to management treatments, predictive modeling, and retrospective analyses. Given the abundance and diversity of fishes inhabiting waterways decreases with groundwater extractions and flow alterations, we used existing interior least tern productivity data and flow data collected from the Central Platte River area for retrospective analyses to assess the influence of forage fish availability on productivity during the brood-rearing season. Our analyses suggest that low flows during the least tern brood-rearing season do not have a negative relationship with interior least tern productivity. As such, we used this indirect line of evidence to build empirical support to assess the forage fish–related hypotheses in the Platte River Recovery Implementation Program's adaptive management plan, and we concluded forage fish abundance does not limit interior least tern productivity on the Central Platte River.

Avian Habitat Following Grazing Native Warm-Season Forages in the Mid-South United States

Native warm-season grasses (NWSG) currently are being promoted for livestock forage and biofuels feedstock in the Mid-South. However, there are no published data on how NWSG managed with livestock in the Mid-South may affect habitat for wildlife. We conducted a study to evaluate habitat for grassland songbirds and northern bobwhite (Colinus virginianus) in response to two cattle grazing treatments in NWSG pastures across three sites in Tennessee, 2010 and 2011. We evaluated vegetation composition and structure along with invertebrate availability during the primary nesting season for grassland songbirds and the typical brood-rearing season for the northern bobwhite. Grazing treatments included full-season (May to August) grazing and early-season (30 days beginning in May) grazing, after which subsequent growth was taken as a biofuel harvest postdormancy. Forage treatments included big bluestem/indiangrass mixture, switchgrass, and eastern gamagrass. Vegetation composition was dominated by the planted forages in all pastures. All forage types and both grazing treatments provided suitable structure for grassland songbirds and bobwhite during the primary nesting season. Full-season grazing maintained suitable structure through the brooding period, with greater openness at the ground level and angle of obstruction, as well as optimal vegetation height (<60 cm). Structure within early-season grazing treatments became dense after cattle were removed with less openness at ground level than what brooding bobwhites typically use. Invertebrate biomass was sufficient in all forage types and grazing treatments to support bobwhite broods. We recommend livestock producers in the Mid-South use full-season grazing that maintains grass height of approximately 40 cm in production stands of NWSG to maximize benefits for grassland birds and northern bobwhite.

Demography, reproductive ecology, and variation in survival of greater sage-grouse in northeastern California

We examined demographic parameters and factors influencing nest survival of female greater sage-grouse (Centrocercus urophasianus) in northeastern California. Additionally, we used known-fate models in program MARK to examine bi-weekly survival rates of females over an 8-month period (Mar–Oct, 2007–2009). Nest survival rate, assuming a 38-day exposure period, was 41% and was positively associated with grass height ( = 0.03, SE = 0.02), but the 95% confidence interval overlapped 0 (95% CI = −0.007–0.767) and the effect of grass height on nest success was likely to be small. Grass height and visual obstruction was greater at nest sites than at random locations, suggesting females selected sites with structurally more closed habitat for nesting. Females that nested under vegetation other than sagebrush (Artemisia spp.) had increased nest survival probabilities, suggesting sage-grouse selection of nest sites is based on vegetation structure more than plant species. Sagebrush canopy cover was considerably lower in our study area (approx. 10% on random plots) compared with sagebrush cover described across the geographic range of sage-grouse (>15%) and sage-grouse use of non-sagebrush plants in our study suggests sagebrush nesting habitat is limited. The overall 8-month survival (breeding season through autumn migration) for female sage-grouse was 49% (SE = 0.06) with most deaths occurring in spring and autumn. Mortalities during spring coincided with nest initiation, incubation, and following hatch when successfully nesting females were tending to chicks. Mortalities in September coincided with dispersal and autumn migration. The survival estimate during the breeding season was greater among known failed nesters ( = 0.69) than females that nested successfully ( = 0.53), indicating female greater sage-grouse were exposed to greater mortality risk during incubation and brood-rearing periods. Greater mortality risk during the breeding season (i.e., nesting and brood-rearing) can have a major impact on greater sage-grouse demography. Conservation and management efforts should focus on enhancing female greater sage-grouse survival during the breeding and brood-rearing season. © 2014 The Wildlife Society.

Fitness consequences of ecological constraints and implications for the evolution of sociality in an incipiently social bee

Ecological constraints such as resource limitation, unfavourable weather conditions, and parasite pressure have long been considered some of the most important selective pressures for the evolution of sociality. In the present study, we assess the fitness consequences of these three ecological factors on reproductive success of solitary nests and social colonies in the socially polymorphic small carpenter bee, Ceratina australensis, based on 982 nests collected over four reproductive periods. Nest site limitation was predicted to decrease opportunities for independent nest initiation and increase the frequency of social nesting. Nest sites were not limiting in this species and the frequency of social nesting was consistent across the four brood-rearing periods studied. Unfavourable weather was predicted to lower the frequency of female dispersal from their natal nests and to limit the brood-rearing season; this would increase the frequency and fitness of social colonies. Daily temperature and precipitation accumulation varied between seasons but were not correlated with reproductive success in this bee. Increased parasite pressure is predicted to increase the frequency and fitness of social colonies because solitary bees must leave the nest unattended during foraging bouts and are less able to defend the nest against parasites. Severe parasitism by a chalcid wasp (Eurytoma sp.) resulted in low reproductive success and total nest failure in solitary nests. Social colonies had higher reproductive success and were never extirpated by parasites. The high frequency of solitary nests suggests that this is the optimal strategy. However, social colonies have a selective advantage over solitary nesting females during periods of extreme parasite pressure, and we suggest that social nesting represents a form of bet-hedging against unpredictable fluctuations in parasite number.

Habitat Use of Nesting and Brood-rearing King Rails in the Illinois and Upper Mississippi River Valleys

Most studies of King Rail (Rallus elegans) have investigated habitat use during the nesting season, while few comparisons have been made between the nesting and brood-rearing seasons. King Rails were located during the nesting season in Missouri using repeated surveys with call playback, and systematic searches for broods were conducted during the brood-rearing season. King Rail adults were located at twelve points in 2006 and 14 points in 2007, and five King Rail broods were located in each year. Water depth was measured and dominant cover type determined for randomly sampled 5-m plots within used and unused habitats. Logistic regression models were fitted to the data and top models were selected from the candidate set using AICc. Nesting adults occurred more often in areas dominated by short (≤1 m) emergent vegetation ( = 0.77 ± 0.27) and deeper water ( = 0.05 ± 0.02). Broods occurred more often in areas dominated by short emergent vegetation ( = 1.19 ± 0.37) and shallow water ( = -0.17 ± 0.06), and avoided areas dominated by tall (>1 m) emergent vegetation ( =-1.15 ± 0.45). A modified catch-curve analysis was used to estimate chick daily survival rates during selected 7-day periods for each year. Daily survival rate ranged from 0.92 ± 0.008 in late June 2007 to 0.96 ± 0.005 in late July 2006. Management plans for King Rails should include the different habitat types needed during the nesting and brood-rearing stages.

FEEDING ECOLOGY OF CANADA GEESE (BRANTA CANADENSIS INTERIOR) IN SUB-ARCTIC INLAND TUNDRA DURING BROOD-REARING

Abstract The diet of adult Canada Geese (Branta canadensis interior) and their goslings was determined during the brood-rearing season in a freshwater tundra habitat using esophageal contents from 25 adult females, 27 adult males, and 59 goslings. Habitat use by geese and the availability and quality of aboveground biomass in wet sedge meadows and around ponds in lichen-heath tundra were also evaluated throughout the summer. During the first four weeks of brood-rearing, adult Canada Geese ate primarily graminoids (>65%), especially leaves of the short form of Carex aquatilis and Eriophorum spp., which had the highest nitrogen concentration (2.5–3.5%). Although graminoids were also important for goslings, they consumed a greater variety of other plant species (68%) than adults, especially in the first two weeks, possibly because of their inexperience. Late in the brood-rearing period, as the nitrogen concentration of graminoid plants declined, adults shifted to a diet composed mainly of berries (>40%, most...

Feeding Ecology of Canada Geese (Branta Canadensis Interior) in Sub-Arctic Inland Tundra During Brood-Rearing

AbstractThe diet of adult Canada Geese (Branta canadensis interior) and their goslings was determined during the brood-rearing season in a freshwater tundra habitat using esophageal contents from 25 adult females, 27 adult males, and 59 goslings. Habitat use by geese and the availability and quality of aboveground biomass in wet sedge meadows and around ponds in lichen-heath tundra were also evaluated throughout the summer. During the first four weeks of brood-rearing, adult Canada Geese ate primarily graminoids (&gt;65%), especially leaves of the short form of Carex aquatilis and Eriophorum spp., which had the highest nitrogen concentration (2.5–3.5%). Although graminoids were also important for goslings, they consumed a greater variety of other plant species (68%) than adults, especially in the first two weeks, possibly because of their inexperience. Late in the brood-rearing period, as the nitrogen concentration of graminoid plants declined, adults shifted to a diet composed mainly of berries (&gt;40%, mostly Empetrum nigrum). At that time, goslings consumed fewer berries (24%) and maintained a higher proportion of nitrogen-rich plants in their diet (53% leaves, mostly graminoids) than adults, presumably to complete their growth. Plant species consumed by geese over the summer indicated a preference for high-quality plants (i.e. those with a high nitrogen concentration). Consequently, wet sedge meadow, the habitat that offered plant species of highest quality, was the habitat most heavily used throughout the summer, particularly around peak hatch. Goose grazing had no effect on seasonal production of aboveground biomass of graminoids, probably because of the relatively low density of the goose population.Écologie alimentaire de Branta canadensis interior pendant la période d’élevage des jeunes dans un milieu d’eau douce sub-arctique

Blood parasites in sage-grouse from Nevada and Oregon.

Peripheral blood smears from 196 adult and yearling female greater sage-grouse (Centrocercus urophasianus) were examined for blood parasites (167 from the breeding and 29 from the brood-rearing season) to determine prevalence of blood parasites, to attempt to correlate infection with chick survival, and to establish base-line values of prevalence in sage-grouse from Nevada and Oregon (USA). Birds were captured and released on two study areas during 1999-2001; Sheldon National Wildlife Refuge (SNWR) in northwestern Nevada, and Hart Mountain National Antelope Refuge (HMNAR) in southeastern Oregon. Birds from a third study area, Beaty's Butte grazing allotment (BB) in southeastern Oregon, were sampled in 2000 and 2001. Overall, 19 birds (10%) were positive for Leucocytozoon lovati (= L. bonasae), 1 (0.5%) for Plasmodium pedioecetii, and 2 (1%) for microfilariae. Although prevalence of L. lovati on HMNAR was 39% during the breeding season in 1999 and 100% during the brood-rearing season in 2000, statistically, prevalence of L. lovati among study areas and years was not different. However, there were statistical differences between capture periods. Overall, 31% of the hens were positive for L. lovati during the brood-rearing season compared to 6% during the breeding season. There was no difference in packed cell volume between infected and non-infected birds and no difference between age-classes. However, mean sage-grouse productivity on HMNAR was higher (1.6 chicks/hen) for non-infected (n = 10) compared to infected hens (0.7 chicks/hen; n = 7), during 1999. Based on these limited observations on HMNAR in 1999, the possible effects that L. lovati may have on young sage-grouse could be detrimental to sage-grouse populations in Nevada and Oregon.

Space and Habitat Use by Greater Snow Goose Broods on Bylot Island, Northwest Territories

The brood-rearing season is a critical time for arctic-breeding geese because plant production is low and the growing season short. Thus, parental geese must efficiently exploit resources if young are to acquire adequate size and condition in preparation for fall migration. Current knowledge of habitat and space use by arctic-breeding geese is limited to some observations of unmarked birds. Thus, we studied habitat and space use of individual radio-marked greater snow geese (Chen caerulescens atlantica) in a high arctic environment. We radiotracked 20 goose families throughout the brood-rearing period in july and August 1989 and 1990, in a 70-km 2 area of wet tundra and upland habitats on Bylot Island, Northwest Territories

Metabolism and energy reserves of brood-rearing horned larks ( Eremophila alpestris)

1. Fasting metabolic rates and energy reserves were determined on Horned Larks ( Eremophila alpestris) captured during the brood-rearing season. 2. Metabolic rates were similar to allometric predictions, and lipid reserves were comparable to those of other brood rearing passerines. 3. Like most small passerines, Homed Larks had only enough lipid reserves to withstand a climatically typical period of overnight fasting. 4. Glycogen reserves were only adequate for a very short fast, which may necessitate protein catabolism for gluconeogenesis.

Brood Habitat Use by Eastern Wild Turkeys in Eastern Texas

We used radio telemetry to study habitat use by eastern wild turkey (Meleagris gallopavo silvestris) females with broods on intensively managed pine (Pinus spp.) forest land in eastern Texas in 1980 and 1981. We sampled habitat at 550 locations for 9 females with broods 1-114 days old and 164 randomly located plots. Females with broods _30 days old selected (P _ 0.10) pole-timber in upland areas and broods >30 days old selected sawtimber in bottomland areas. Low timber stocking, low density of midstory trees, abundant herbaceous ground cover, and control burned areas were selected (P 0.10) by all broods. J. WILDL. MANAGE. 53(2):479-482 Quality of habitat for turkeys is often assessed by winter carrying capacity; however, habitat quality during the brood-rearing season (spring and summer) may be more important in limiting wild turkey populations (Hillestad and Speake 1970). Hurst (1981) emphasized that information on habitat preferences of turkeys is available; however, specific habitat characteristics have not been adequately measured or quantified. Our objective was to assess habitat characteristics for eastern wild turkey females with broods on intensively managed pine forest land in eastern Texas. Temple-Eastex Incorporated, Diboll, Texas, allowed us to use the study area. The Louisiana Wildlife and Fisheries Commission and the Mississippi Department of Wildlife Conservation supplied turkeys for the study. Funding was provided by the Wildlife Management Institute, American Petroleum Institute, Caesar Kleberg Research Foundation, and Texas Parks and Wildlife Department Federal Aid Project W-108-R-4. This is Article TA-22949 of the Texas Agricultural Experiment Station, Texas A&M University.

Reduced plasma lh concentration in quail exposed to the organophosphorus insecticide parathion

Native warm-season grasses (NWSG) currently are being promoted for livestock forage and biofuels feedstock in the Mid-South. However, there are no published data on how NWSG managed with livestock in the Mid-South may affect habitat for wildlife. We conducted a study to evaluate habitat for grassland songbirds and northern bobwhite (Colinus virginianus) in response to two cattle grazing treatments in NWSG pastures across three sites in Tennessee, 2010 and 2011. We evaluated vegetation composition and structure along with invertebrate availability during the primary nesting season for grassland songbirds and the typical brood-rearing season for the northern bobwhite. Grazing treatments included full-season (May to August) grazing and early-season (30 days beginning in May) grazing, after which subsequent growth was taken as a biofuel harvest postdormancy. Forage treatments included big bluestem/indiangrass mixture, switchgrass, and eastern gamagrass. Vegetation composition was dominated by the planted forages in all pastures. All forage types and both grazing treatments provided suitable structure for grassland songbirds and bobwhite during the primary nesting season. Full-season grazing maintained suitable structure through the brooding period, with greater openness at the ground level and angle of obstruction, as well as optimal vegetation height (< 60 cm). Structure within early-season grazing treatments became dense after cattle were removed with less openness at ground level than what brooding bobwhites typically use. Invertebrate biomass was sufficient in all forage types and grazing treatments to support bobwhite broods. We recommend livestock producers in the Mid-South use full-season grazing that maintains grass height of approximately 40 cm in production stands of NWSG to maximize benefits for grassland birds and northern bobwhite.

Investigation into Brood Diseases of Bees

IN May 1934, an investigation into the brood diseases of bees was commenced at Rothamsted Experimental Station, the British Bee-Keepers' Association undertaking to supply half the annual cost of the work (£250 per annum) and the Agricultural Research Council the remainder. As a result, Dr. H. L. A. Tarr was appointed, and has worked continuously on the problem since that time. He has confirmed the fact that American foul brood is caused by a spore-forming organism, Bacillus larvce, and that its incidence is independent of the strength of the bee colony. European foul brood, on the other hand, is a disease which usually affects weak colonies of bees early in the brood-rearing season, and is probably caused by Bacillus pluton, a curious organism which has so far resisted all attempts made to cultivate it, in association with other organisms. He has also shown that a third condition known as addled brood is very, prevalent in Great Britain, and has constituted almost one third of the cases of brood disease sent in for examination. The Bee Research.Committee at Rothamsted and the British Bee-Keepers' Association are unanimously of the opinion that the investigation should be continued, particularly in connexion with methods of treatment, but the latter have asked that Rothamsted should collect the contributions directly. The Agricultural Research Council has sanctioned an increased grant of £300 for the current year on condition that a sum of not less than £250 is collected from other sources. In the circumstances, Rothamsted Experimental Station is making an appeal for contributions from interested individuals in order that this important investigation may be continued.