Brood Movements Research Articles

Brood sorting by ants: two phases and differential diffusion

Leptothorax ant colonies sort their brood in concentric annuli with the smallest items in the middle and the largest on the periphery. Such brood sorting is a prime example of collective structure formation by social insects. Its underlying mechanism, however, is still not understood. We tested the hypothesis that brood sorting has two phases: the phase of clustering, proposed earlier, is followed by a phase of spacing, when ants move brood items away in a random direction but in a type-specific way so that items of different brood types spread out to a different extent. We hypothesized that in phase 2, spacing, items of the smallest brood type spread out the least and end up in the centre, whereas items of the largest brood type spread out the most and end up on the periphery. We found two distinct phases in the direction of brood movement during brood sorting associated with nest emigration. In phase 1, ants moved brood items in the direction away from the nest entrance. This was the clustering phase. In phase 2, ants moved brood items in a random direction. This was the spacing phase. Ants moved smaller items for longer than larger items. This is consistent with the hypothesis that ants put down brood items as a function of their weight. The diffusion coefficient and the frequency of movement were different for different brood types. The measure of the average spread (root-mean-square displacement) for each brood type was consistent with their order from the centre to the periphery of the sorted brood structure. The process underlying this spread, however, could not be simple diffusion since the movements of different brood types are interdependent. We discuss the mechanisms that could underlie the switch between the two phases.

Adoption of Chicks by the Pied Avocet

Data on the occurrence and frequency of adoption of chicks by adult Pied Avocets (Recurvirostra avosetta) were collected by monitoring individually color-banded chicks on alkaline lakes in the Kiskunság National Park in central Hungary between 1998 and 2000. Fifty-three adoptions were observed, and 22% of the resighted broods (N = 244) contained on average 1.7 (range 1-6) adopted chicks. Ninety-two chicks, or 13% of the color-banded chicks (N = 697) were adopted. The frequency of adoption was similar among years and was positively related to the number of pairs within a colony. At least 60% of the adoptions occurred in the nesting colonies, whereas adoptions during brood movements or in the brood-rearing areas, as well as brood amalgamations, were rare. More than two-thirds (68%) of the adopted chicks in the colony left the natal brood and joined other broods voluntarily. The remaining adopted chicks were the last to hatch in their own brood and were adopted into another brood after being left behind by their parents. Adults did not behave aggressively toward young alien chicks and always accepted them. Adoption appears to be initiated by chicks in Pied Avocets, and it may be associated with small fitness costs, or may even provide benefits, for the adoptees or the adopting adults.

Influence of Female Age and Body Mass on Brood and Duckling Survival, Number of Surviving Ducklings, and Brood Movements in Redheads

AbstractI documented brood and duckling survival, the number of surviving ducklings, and brood movements of Redheads, and examined the association between these variables and female age and body mass. Redhead brood success was 55% and duckling daily survival rates averaged 0.868. Female body mass, but not age, was related to brood and duckling survival and the number of surviving ducklings. Successful females were heavier and produced more ducklings. All brood-movement measures differed between successful and unsuccessful females, however, the distance of the first move between wetlands accounted for the most variability in brood success. Increased body mass, but not age, was associated with longer first brood movements.

Influence of Female Age and Body Mass on Brood and Duckling Survival, Number of Surviving Ducklings, and Brood Movements in Redheads

Influence of Female Age and Body Mass on Brood and Duckling Survival, Number of Surviving Ducklings, and Brood Movements in Redheads

Soil-Free Collection of Argentine Ants (Hymenoptera: Formicidae) Based on Food-Directed Brood and Queen Movement

The movement of Argentine ant, Linepithema humile (Mayr), colonies was studied in the laboratory. Workers transported brood from the main colony to satellite nests within 2 h. Queens also moved into the satellite nests. Up to 70% of the brood were moved out of the main colony by 48 h. Although most of the brood and queens migrated to a satellite nest 60 cm from the main nest, a substantial number of brood and queens moved 12.2 m to a nest 60 cm from a food source. We subsequently employed these findings to induce a portion of a field colony of L. humile to enter artificial colony dishes within the laboratory. Workers, brood, and queens were collected continuously and effortlessly using this technique.

INFLUENCE OF FEMALE AGE AND BODY MASS ON BROOD AND DUCKLING SURVIVAL, NUMBER OF SURVIVING DUCKLINGS, AND BROOD MOVEMENTS IN REDHEADS

I documented brood and duckling survival, the number of surviving ducklings, and brood movements of Redheads, and examined the association between these variables and female age and body mass. Redhead brood success was 55% and duckling daily survival rates averaged 0.868. Female body mass, but not age, was related to brood and duckling survival and the number of surviving ducklings. Successful females were heavier and produced more ducklings. All brood-movement measures differed between successful and unsuccessful females, however, the distance of the first move between wetlands accounted for the most variability in brood success. Increased body mass, but not age, was associated with longer first brood movements.

Wood Duck Brood Movements and Habitat Use on Prairie Rivers in South Dakota

Wood duck (Aix sponsa) populations have been increasing in the Central Flyway, but little is known about wood duck brood rearing in prairie ecosystems. We compared movements and habitat use of radiomarked female wood ducks with broods in South Dakota on 2 rivers with contrasting prairie landscapes. The perennial Big Sioux River had a broad floodplain and riparian forest, whereas the intermittent Maple River had emergent vegetation along the river channel. Movements between nest sites and brood-rearing areas were longer on the Maple River than on the Big Sioux River (P = 0.02) and were among the longest reported for wood duck broods. Movements on the Big Sioux River were longer in 1992 (P = 0.01), when the floodplain was dry, than in 1993 or 1994. Before flooding occurred on the Big Sioux River, broods used semipermanent wetlands and tributaries outside the floodplain; thereafter, females selected forested wetlands along the river. Broods on the Maple River used emergent vegetation along the river channel throughout the study. Because median length of travel to brood-rearing areas was 2-3 km, we recommend maintenance of brood-rearing habitat every 3-5 km along prairie rivers. Wildlife managers should encourage landowners to retain riparian vegetation along perennial rivers and emergent vegetation along intermittent streams to provide brood-rearing habitat during wet and dry cycles.

Brood movement and natal dispersal of hazel grouse Bonasa bonasia at Changbai Mountain, Jilin Province, China

Brood movement and natal dispersal of hazel grouse Bonasa bonasia at Changbai Mountain were studied using radio telemetry in 1993–94. Most chicks hatched during late May to early June. Only hens accompanied three radio‐tracked broods. After wandering for 30–35 days, broods 1 and 3 became relatively sedentary in second‐growth forest, 1.6–1.7 km from their nests. Broods 1 and 3 disintegrated when chicks were 80 and 69 days old. Based on radio‐tracking, it is suggested that the impetus for one brood's disintegration was that the hen left its brood. Female 2 lost her chicks about 20 days after hatching. The hens returned to their spring home ranges after brood dissolution. Three radio‐marked chicks dispersed 4.8–5.7 km in mid‐September. It is concluded that, in general, the hazel grouse is an active disperser in natural habitats.

Habitat Selection and Diet of Lapwing Vanellus vanellus Chicks on Coastal Farmland in S. W. Sweden

1. Habitat use by colour-marked lapwing Vanellus vanellus broods was studied at three coastal farmland sites in S.W. Sweden from 1987 to 1990. 2. Initial brood movements between nest sites and home ranges used for chick-rearing varied between 7 and 332 m. At all sites, the proportions of habitats within lapwing home ranges differed from availability. Sea shore pasture was relatively the most used habitat. Lapwings selected home ranges with lower proportions of arable fields and moist pasture relative to sea shore pasture, and at two sites also to the shore, than expected if choice was due to availability. 3. Lapwing broods did not select feeding habitats in relation to availability. Feeding on sea shore pasture, and at one site also on the shore, occurred more frequently than expected relative to the use of arable fields and moist pasture. Foraging on the shore was constrained by variation in sea water level. Broods from nests on arable fields left the nest site habitat, and used the same feeding habitats as broods hatched on pastures. 4. Chicks fed on a wide variety of prey organisms, representing terrestrial, marine and freshwater invertebrates. Sampling of potential food supply suggested that numbers and biomass of invertebrates included in the chick diet were greater on a sea shore pasture than on an adjacent moist pasture. 5. Loss of important chick foraging habitats and isolation of nest sites and chick-rearing habitats, caused by changes in agricultural land use, have probably contributed to the decline of lapwings breeding on farmland in Europe. The results are related to conservation of this and other waders breeding on farmland.

Survival and Movements of Canvasback Ducklings

Because canvasback (Aythya valisineria) breeding areas have been reduced by wetland drainage and because density-dependent factors that limit survival of ducklings are poorly understood, we studied brood and duckling survival during 1983-90 and overland brood movements during 1988-89 on 2 study blocks (15.8 km 2 each) near Minnedosa, Manitoba. One block was designated as the experimental area where canvasback duckling production was experimentally enhanced, whereas the other block was an unmanipulated control. Individually marked female canvasbacks with ducklings were monitored to test the effects of canvasback brood density, presence of parasitic redhead (A. americana) ducklings, hatching date, and pond water levels on canvasback duckling survival. We observed no between-block differences in mean daily survival rates of canvasback ducklings during 1983-86. The experimental high-density area had higher (P < 0.05) duckling survival probabilities during 1987-88. Duckling survival was significantly related (P = 0.033) to duckling density but not (P = 0.56) June wetland water levels. Duckling survival probabilities were highly variable among years (range = 0.027 ± 0.007 [SE] to 0.623 ± 0.004 [SE]); survival rates in 1989-90 during severe drought were much lower than in previous years. We observed no consistent effect of hatching date on duckling survival among years. On the experimental study block in 1988, canvasback ducklings in broods containing parasitic redhead ducklings had lower (P = 0.013) survival during the first 7 days of life. Canvasback broods were observed on an average of 4 different ponds and traveled an average total overland distance of 1.5 km with no between-block differences. Density-dependent mortality of ducklings was not a factor in limiting recruitment of canvasbacks in the Minnedosa area.

Habitat-related variation in movements and fledging success of American black duck broods in northeastern Nova Scotia

Female American black ducks (Anas rubripes) are known to move their broods from low- to high-nutrient rearing sites. We studied the extent of brood movement and fledging success in a northeastern Nova Scotia watershed. Annually, about half the broods moved either overland or along three rivers from small, widely dispersed oligotrophic–mesotrophic wetlands to a large hypertrophic tidal marsh. Mean brood size at fledging was 3.50 in the tidal marsh but 7.05 at the dispersed freshwater wetlands. Females that remained at dispersed sites fledged more ducklings than females that moved to the marsh. Attrition occurred predominantly in the marsh or in transit. Females fledged fewer young when they raised broods at the marsh than when the same females raised broods at inland sites. Females were as successful at nutrient-poor sites as at nutrient-rich sites. The study suggests that concentrating birds in nutrient-rich sites may be counterproductive in terms of female reproductive fitness and population recruitment.

Movements and survival of Common Goldeneye broods near Sudbury, Ontario, Canada

We examined movements and survival of Common Goldeneye (Bucephala clangula) broods in a highly acidified area on the Canadian Precambrian Shield near Sudbury, Ontario, during 1989 and 1990. When data from the 2 years were combined, a total of 16 females had led their broods from nesting to rearing lakes, while only 4 had raised their broods on the nesting lake. Initial brood-rearing lakes contained a greater biomass of invertebrate prey and were closer to neighbouring lakes than corresponding nesting lakes. Eight broods undertook 17 secondary movements between rearing lakes. These movements were not related to differences between lakes in prey biomass or distance to neighbouring lakes. Daily survival rates of age-class I and age-class II ducklings did not differ between years. When data from the 2 years were combined, it was found that duckling survival was not related to brood movements or prey biomass. Duckling survival was higher on clustered lakes than on isolated lakes. The availability of alternate brood-rearing lakes with sufficient invertebrate prey, in addition to the primary brood-rearing lake, may be an important factor influencing Common Goldeneye brood movements and survival in our study area.

Mallard Brood Movements and Wetland Selection in Southwestern Manitoba

Wetland drainage has heavily impacted mallard (Anas platyrhynchos) breeding areas and decreased the amount of wetland area available to mallard broods. Also, habitat selection by mallard broods is poorly understood. Therefore, we investigated habitat use by mallard broods, monitored habitat availability, and tested for habitat selection by monitoring 29 mallard hens and their broods via radio telemetry in southwestern Manitoba, 1987-89. Habitat availability varied (P 0.10) by broods

Growth and Survival of Willow Grouse Chicks in Relation to Home Range Size, Brood Movements and Habitat Selection

Spacing, movements and mortality of Willow Grouse Lagopus 1. lagopus broods were studied using radio-telemetry during three breeding seasons on a small island in northern Norway. Chicks survived worse during two cold summers with few insects than in a warm summer with many. In cold weather, many died at 3-5 days. Broods selected forests, bogs and fens, and shore vegetation which supported the largest number of insects. Mean differences between years in spacing and brood movements were small. Within years, growth was slower and survival lower among those broods with the greatest mobility and largest home ranges. Broods occupying small home ranges restricted their movements to areas especially rich in insects, whereas longer movements were made in poorer habitats. There appeared to be a dominance hierarchy among broods which effectively prevented them from occupying the same areas.

Brood Movements in Grouse and Waders as Defence against Winstay Search in Their Predators

On tente de preciser la strategie de recherche manifestee par le predateur (Buteo buteo par exemple) en relation avec la dispersion de la proie et l'on resume les donnees sur l'existence des deplacements des couvees de tetraonides et sur le comportement de defense des poussins contre la poursuite par les predateurs; un modele graphique est construit pour representer la valeur de survie des deplacements de la couvee comme strategie de defense

Effects of Changing Agriculture on Ring-Necked Pheasant Brood Movements in Illinois

Suivant le type de culture les jeunes Phasianus colchicus peuvent se deplacer ou non (ils se deplacent notamment dans le cas de monocultures (jusqu'a 1,6 km a partir du site de nidification))

Une étude des relations spatiales entre jeunes avocettes sur leurs lieux d’élevage

This study examines the spatial organization in broods of young Avocets, Recurvirostra avosetta, on their rearing grounds. In order to describe the development of the ranging behaviour within the colony, detailed observations are reported on one of these broods (brood A), studied from hatching to 60 days of age. Before the young were fledged, there was a small overlap in the daily ranges of different broods, and these moved slightly on successive days. This brood spacing is achieved through the territorial behaviour of the parents. In contrast, interbrood disputes never arise. Brood movement in the colony occur when the parents lead their young away or when a resident family is forced to leave its area, after being supplanted by another. Home range size of brood A shows a discontinuous increase, up to 47 ha, as a result of the movements of the young which often shift around. During the pre-fledging period (40 days), brood A did not wander through its whole area ; instead, the home-range (including the nest-site) could be subdivided into five parts, each of which was used intensively for several consecutive days. After fledging of the young, a shift in the home-range use was observed. Between 40-52 days of age, two exclusive areas were visited in flight, with a pronounced daily variation. Moreover, a predominent activity (resting or feeding) was associated with each of them. From 53 to 60 days of age, brood A expanded its home range considerably, by using a new area 600 m apart from the rearing site. During the post-fledging period, territorial behavior became less consistent and the birds (adults and juveniles) gradually form small unstable flocks. Brood movements within the colony and social relationships between juveniles both emphasize the dynamics of the spatial organization in the Avocet colony.

Events following queen removal in colonies of european-derived honey bee races (Apis mellifera)

The timing of queen rearing and swarming are described after queens were removed from colonies of European-derived honey bee races. Queen cell construction began within one day of queen loss, and 91 % of the queens which emerged were eggs at the time of queen loss. Queen cells were evenly distributed over the comb face, and 4 % of the brood reared as queens were moved from worker cells to queen cups. There was considerable variation in the number of queen cells which were viable, aborted, and unoccupied. Brood mortality was high following queen loss. Six of the eight study colonies swarmed following the emergence of a virgin queen. These results differ from previous studies of queen loss in tropically-evolved honey bees in the timing of new queen production and the frequency of queen-loss swarming and of brood movement by workers.

Movements and Wetland Selection by Brood-Rearing Black Ducks

Movements and wetland selection by brood-rearing black ducks (Anas rubripes) were studied in Maine during 1977-80. Eight radio-marked hens moved their broods an average of 1.2 km from the nest to rearing pond, but only 1 hen initiated secondary brood movements. Half of the 85 broods reared in the study area used only 3 wetlands, and most rearing ponds contained active beaver (Castor canadensis) colonies. Brood-rearing hens preferred Emergent ponds over lakes and Evergreen Scrub-Shrub wetlands, and did not occupy Dead Scrub-Shrub, Unconsolidated Bottom, or Aquatic Bed wetlands. Rearing ponds were large and possessed extensive areas of flooded mountain alder (Alnus incana), willow (Salix spp.), and herbaceous vegetation. Wetlands avoided by brood-rearing hens were those with large areas of open water, submergent aquatics, or ericaceous shrub vegetation. J. WILDL. MANAGE. 46(3):615-621 The ability of female black ducks to select brood-rearing ponds that will fulfill the changing food and habitat requirements of growing ducklings increases the prospects for brood survival. Many researchers (V. D. Stotts, unpubl. rep., Maryland Game and Inland Fish Comm., Fed. Aid Proj. W-30-R-7, 1959; Reed 1970; Hepp and Hair 1977) have recognized the importance of rearing areas and have identified the types of wetlands used by black duck broods. However, comparatively little is known about the wetland habitat components that serve as proximate factors (Hilden 1965) in the selection process. Studies of primary and secondary brood movements (Evans et al. 1952, Berg 1956, Stewart 1958, Beard 1964, Ball 1973) indicate that ducks actively select rearing areas. Wright (1954) observed a black duck hen leading her brood >3.2 km overland to a rearing area, and Young (1967) discussed the overland movements of 2 broods to a large pond >1.6 km away. Detailed data on brood movements of inland-nesting black ducks have been unavailable, but are necessary for an understanding of duckling survival and habitat selection. We investigated the selection of wetlands and habitat components by radio-marked and unmarked female black ducks, and the movements of marked, brood-rearing hens. We acknowledge the work of field assistants J. M. Connolly, J. D. Schoultz, J. Sease, and S. E. Staples. T. J. Dwyer, L. D. Flake, and G. M. Haramis provided comments on early drafts of the manuscript. Financial support for this study was provided in part by contract #14-160008-2125 from the Migratory Bird and Habitat Research Laboratory, U.S. Fish and Wildlife Service, and by the School of Forest Resources, University of Maine, Orono. STUDY AREA AND METHODS The 151-km2 study area was 30 km southwest of Bangor, Maine in the northern hardwoods-spruce ecoregion (Bailey 1978). Forty-four of the 118 study wetlands were created or modified by beaver. Most ponds were classified as EverI Present address: Colorado Division of Wildlife, Research Center, 317 W. Prospect, Fort Collins, CO 80526. J. Wildl. Manage. 46(3):1982 615 This content downloaded from 157.55.39.147 on Sun, 07 Aug 2016 07:03:12 UTC All use subject to http://about.jstor.org/terms 616 BROOD-REARING BLACK DUCKS* Ringelman and Longcore green or Deciduous Scrub-Shrub, Deciduous Forested, or Persistent Emergent wetland types (Cowardin et al. 1979), and ranged in size from 0.1 to 64.2 ha. A detailed description of the study area was presented by Ringelman (1980:3). Data on brood movements were attained by following radio-marked females which were captured before brood-rearing with nest traps (Coulter 1958) or rocket nets. Females were instrumented with 25-g, back-mounted transmitters and monitored 2-3 times per day with a mobile, null-peak tracking system using conventional telemetry techniques. Observations of unmarked broods, supplemented with telemetry records of radio-marked hens, provided data that were used in the analysis of habitat selection. Rearing ponds were defined as wetlands used by a brood for >24 hours. Brood surveys were conducted on all rearing ponds every 6-10 days from the last week in May through the end of July 1977-80. Most observations were made from tree stands 3-15 m above the water's surface. Black duck broods were characterized by number and age of ducklings (J. B. Gollop and W. H. Marshall, unpubl. rep., Miss. Flyway Tech. Sect., 1954), because a unique combination of these characteristics enabled us to re-identify individual broods during subsequent visits. Details of our brood survey methods are described elsewhere (Longcore and Ringelman 1980). The hypothesis that brood use differed significantly from the availability of each wetland class was tested with a z statistic (Neu et al. 1974). A stepwise forward discriminant analysis (Klecka 1975) was performed to identify individual habitat components characteristic of wetlands used vs. those avoided by broods. Twenty-eight habitat components (Table 1) were used as discriminating variables. Preliminary analyses indicated that variable means were proportional to standard deviations, so a logarithmic transformation (log[x + 1]) was applied to all data (Zar 1974:184) to avoid problems created by heteroscedasticity and non-normality (Box and Cox 1964, Eisenbeis and Avery 1972).