Average Number Of Nests Research Articles

Nesting habits of Baya Weaver Ploceus philippinus (Linnaeus, 1766) on power and television cables in the agricultural landscape of Kallakurichi district, Tamil Nadu, India

The nesting habits of Baya Weaver Ploceus philippinus with nesting site (e.g., power and television cables), source of nest materials, various developmental stages of nests, abnormal nests, number of individuals and their association with other bird species, and threats to their nests were studied between March and September 2021 in the agrarian landscapes of 42 villages in Kallakurichi District, Tamil Nadu. A total of 155 nest colonies containing 1,725 nests of various developmental stages and 1,993 adult birds were counted on power/television cables. The number of nests per colony found varied from one to 57. The average number of nests per colony was eleven. Baya Weaver had preferred power/television cables as nesting sites in the study area in spite of availability of potential nest-supporting trees, such as Cocos nucifera and Borassus flabellifer within 500 m radii from cables bearing nests. Birds used fibres of sugarcane leaves (Saccharum officinarum) for the construction of nests. Out of 778 helmet stage nests observed, 90% (n = 716) helmet stage nests had clay deposits on their inner walls and no clay deposits were found in the remaining 10% (n = 62) helmet stage nests. Eleven types of abnormal nests constituted 17% (n = 286) of the total nests. Sixteen other bird species (e.g., birds of order: Passeriformes, Coraciiformes, Piciformes, Cuculiformes and Columbiformes) were found associated with the individuals of Baya Weaver. These bird species strictly shared similar roosting and foraging grounds. The avian predators such as House Crow Corvus splendens, Large-billed Crow Corvus macrorhynchos, Black Drongo Dicrurus macrocercus, Rufous Treepie Dendrocitta vagabunda, Coucal Centropus senegalensis, and Shikra Accipiter badius had damaged the nests, eggs and chicks. The study revealed that about 1.1% nests (n = 197) were probably damaged by these avian predators. Power cables in the study sites had provided suitable nesting sites for Baya Weavers. The causes for utilization of power cables as nesting sites in larger geographical areas require further studies.

Analysis of the Spatial Distribution of Settlements of Red Wood Ants in the Baikal Region

Outbreaks of defoliating insects constantly emerge and spread in the heavily forested Baikal region. Biological control is the approach of choice in pest management, and red wood ants are used to control defoliating insects at their outbreak sites. The purpose of the present paper is to choose the forest plots with complexes of red wood ant nests in the Baikal region and to estimate the level of protection of these plots from defoliating insects using hybrid geoinformation system (GIS). The Institute for System Dynamics and Control Theory SB RAS geoportal (http://geos.icc.ru) is the hybrid GIS. During fieldwork, 101 nests of F. aquilonia Yarr. and 20 nests of F. lugubris Zett. were found. One hundred and two nests (88 F. aquilonia nests and 14 F. lugubris nests) formed nest complexes and were located on 18 forest plots. Two parameters were used to estimate protection level of forest plots from defoliating insects: the average number of nests per 1 hectare (settlement density) and the total area of dome bases of all anthills located on 1 hectare (power of the nest complex). The research revealed that only four forest plots (“Uzury”, “Khalgay”, “Onguren_2”, and “Onguren_3”), situated in the mountain taiga pine landscape, were protected from defoliating insects (settlement density ≥5 nests/ha and power of nest complex >6 m2/ha). Besides, the complex of nests in the “Onguren_2” forest plot can be a source for capture of filial nests. The “Arshan_2” forest plot, situated in the mountain taiga dark coniferous landscape of reduced development, had the lowest density of settlements of ants (less than two nests per hectare). The state-of-the-art hybrid GIS is a tool that can be used to quickly and efficiently discover and analyze the spatial distribution of settlements of red wood ants

Baseline Alligator Nesting Data in Arthur R. Marshall Loxahatchee National Wildlife Refuge to Inform Monitoring

Abstract Monitoring key ecological attributes helps land managers understand the current state of the resource and decide if management action is necessary. Baseline data on spatial and temporal variability of attributes to be monitored is important for development of successful monitoring programs. In this study, I collected data from 2000 to 2004 on American alligator Alligator mississippiensis nesting in the Arthur R. Marshall Loxahatchee National Wildlife Refuge to determine feasibility of conducting alligator nest surveys and collect baseline data on alligator nesting status and variability. I used nest data to provide examples of potential monitoring strategies for tracking trends over time or understanding the effects of different hydrologic conditions on alligator nesting. Conducting ground surveys with airboats in Arthur R. Marshall Loxahatchee National Wildlife Refuge proved to be an effective method of finding alligator nests. Number of nests per 1.6 km × 1.6 km (256-ha) plot ranged from 1 to 12, and by year from 28 to 53. Overall, average number of nests per hour ranged from 1.8 ± 0.26 (SE) in 2000 to a low of 0.84 ± 0.08 in 2004. Using data from this study for the six plots sampled each year, and assuming no change in variability, power analysis shows that 10 y of sampling would allow for detection of an annual 10% change in number of nests per hour, with power and level of certainty set equal at 90% (β and α both 0.10). Additionally, 15 y of data would allow for a detection of a 5% change per year. Thirty-seven plots per area would be necessary to assess a 40% difference in number of alligator nests per hour in areas with different hydrologic conditions with power and level of certainty at 90%. Land managers can use these data and analyses, along with examples of monitoring strategies, to guide development of more specific monitoring protocols that address restoration objectives and management actions throughout the Florida Everglades.

Efficiency of funnel traps in controlling pine processionary moth

Changing climate conditions have allowed the pine processionary moth [Thaumetopoea pityocampa (Den. & Schiff. 1775) (Lepidoptera: Notodontidae: Thaumetopoeidae) and T. wilkinsoni Tams. 1925 (Lepidoptera: Notodontidae: Thaumetopoeidae)] which is one of the most important insects in Mediterranean forest ecosystems, to distribute to larger areas. More effective control of this moth is necessary to prevent its expansion to northern and higher altitudes. Mechanical, biological, chemical, and biotechnical control methods are currently being applied. These methods are either not effective alone, are very expensive, have low impact, or are problematic with respect to the environmental and human health. The purpose of this study was to develop a new approach to control the pine processionary moth and to develop an economical, ecological, and effective trap exploiting its behavioural characteristics. Traps attached to tree trunks caused mature larvae to be trapped as they landed on the soil in convoys to become pupa. In 2013, the average number of nests per tree was 4.7, while it decreased to 2.0 in 2015; furthermore, the average number of larvae decreased from 265 to 57. As a result of this 3-year study, it was found that these traps could catch nearly all of the adult larvae and reduce the moth population; it was also evident that these traps can be used as a new alternative method to control the pine processionary moth, alone or in combination with other methods.

Pendugaan Populasi Penyu Hijau (Chelonia Mydas) di Pulau Jemur Kabupaten Rokan Hilir Riau

Research on the estimation of green turtle population (Chelonia mydas) was conducted in Jemur Island of Rokan Hilir Regency of Riau Province in May-June 2012. The purpose of this research is to estimate the green turtle population in Jemur Island Rokan Hilir regency, Riau Province. The research method used is the absolute method of absolute sampling that results in the number of population estimates in the form of the number of individuals per unit of sand surface units or habitats observed. The results showed that the number of different individuals as many as 229 nests. The condition of Jemur Island indicates the suitability of location for green turtle habitat to lay and incubate eggs. Physical factors corresponding to the distribution of saraang are said to be productive, ie the average number of nests per day of 8 (eight) nests or 8 (eight) different individuals. Of the 229 nests observed, the depth of the hive ranged from 60cm - 80cm and did not significantly affect the number of eggs placed with the results of correlation (r = 0.43).

Golden eagle Aquila chrysaetos in Xinjiang: Nest-site selection in different reproductive areas

The reports about the geographical distribution, reproductive ecology and population dynamics of the golden eagle Aquila chrysaetos were mostly descriptive in China, and lack quantified studies for the nest-site selection of this species. We carried out our investigations by direct observations in the northern Xinjiang during 2004–2011, attempting to reveal the main factors that affected on the nest-site selection and the differences of ecological variables of reproductive areas in the species (Mts. Tian Shan spurs and Mt. Kalamaili). We measured 38 nests totally belonging to the 16 home ranges. The average number of nests in each home range was 2.38±0.41, and with no significant difference (P>0.05) between different reproductive areas. In all cases golden eagles nested on cliffs (n=38) in our study area. The average external diameter of nests was (198.4±8.2) cm × (159.3±14.2) cm (Mean±SE, n=9), and inner diameter was (91.1±4.4) cm. The nest-site selection was extremely significant difference (P<0.01) for the different reproductive areas, i.e. elevation, hill height, nest-site height, cliff height, gradient, the distance to water resource, and the distance to residential area. The distance from the cliff bottom and from the cliff top were significant difference (P<0.05). However, the slope position, nest position, distance to unpaved and paved road were not significant difference (P>0.05). In Mts. Tian Shan spurs, the elevation was obviously selective (χ2=13.99, df=4, P<0.01), and mainly nested in altitude of 1 932–2 197m, where the main aspects were SW (36.4%, n=22) or SE (31.8%), and the slope gradient was above 85°. In Mt. Kalamaili, also it was found the significant differences for elevations (χ2=11.44, df=3, P<0.01), the eagle mainly nested in altitude of 1 112–1 423m, with aspects of NW (68.8%, n=16), and the gradient was relatively flat. In reproductive areas, eagles nested in the mid-slope parts and higher slope position (92.1%, n=38). Eagles nested far from the seriously disturbed places by human, especially roads, residential area, mineral mines, etc. The principal component method of the factor analysis indicated that there were four main factors affecting on the nest-site selection by golden eagle in Mts. Tian Shan spurs: human disturbance factor (eigenvalue is 4.800, Ratio of contribution is 34.28%), nest position factor (3.002%, 21.44%), prey factor (2.601%, 18.58%), and terrain factor (1.305%, 9.32%). In Mt. Kalamaili, there are five main factors as following: terrain factor (eigenvalue is 5.110, Ratio of contribution is 34.07%), nest position factor (3.747%, 24.98%), human disturbance factor (2.123%, 14.16%), prey factor (1.584%, 10.56%), and gradient factor (1.111%, 7.41%). To conclude, human disturbance and landscape are the two main factors affecting on the nest-site selection of the eagle. The nest-site selection is a result of trade-off among the human disturbance, landscape and prey amount. Eagles take corresponding strategy of nest-site selection for adaptation to the various environments, having different conditions for the eagle reproductive. So, we recommended the improvement of the habitat fitness for the increasing of the reproductive success of the golden eagle.

Breeding Status of Black-naped and Roseate Terns in the Yaeyama Islands, Ryukyu Islands, Japan, in 2001

The distribution of breeding sites, number of nests, and timing of egg laying of the threatened Black-naped Tern Sterna sumatrana and Roseate Tern S. dougallii was surveyed across most of the Yaeyama Islands, located among the southern Ryukyu Islands, in the 2001 breeding season. Black-naped Terns bred in 42 sites that included 1-64 nests (average number of nests, 14.8±16.5 SD). Roseate Terns bred in six sites that included 1-123 nests (average number of nests, 59.8±57.3 SD). At most of the breeding sites, Black-naped Terns started to lay eggs in late June; while at some breeding sites, breeding commenced in early or mid July. Roseate Terns started to lay eggs in late June at two sites and in mid June at the other site.

Assessing Habitat Use by Breeding Great Blue Herons (Ardea herodias) on the Upper Mississippi River, USA

Abstract Approximately 7,610 to 3,175 pairs of Great Blue Herons (Ardea herodias) nested along 420 river km of the Upper Mississippi River (UMR) from 1993 to 2003. Numbers declined precipitously in the mid-1990s stabilizing somewhat in the early 2000s. The average number of nests in colonies was 349 (SD = 283). Annual colony turn over rate for the eleven year period was 0.15 and ranged from 0.06 to 0.29 each year. The number of years that a colony was active was positively correlated with the average number of nests present while the colony was active. Of the eight colonies active in 1993 that averaged more than 349 nests, four were abandoned by 2003. Only one colony grew to greater than 349 nests during the study period. Custer et al. (2004) suggested that herons on the UMR may be limited by forage resources or foraging habitat and social factors, as evidenced by the even spacing of colonies that reflects the maximum feeding range of herons on the river. To rule out nesting and foraging habitat limitatio...

The impact of American mink Mustela vison on water birds in the upper Thames

Summary 1. The effect of mink predation on water birds during the breeding season was studied between March and September 1996 in a 33‐km long stretch of the upper Thames river, England. 2. Mink presence significantly affected the density of breeding coots and the number of chicks hatched per pair of coots, as well as the average number of nests per pair of moorhens and the percentage of moorhen clutches hatched. 3. Mink diet during the birds’ breeding season (March–September) was studied through scat analysis. Ralliformes (coots or moorhens) represented 10% of the ingested biomass and were the fourth prey in importance after rabbits (45%), fish (25%) and small mammals (14%). Mink obtained 11% of their energy requirements from coots and moorhens. 4. Impact of predation by mink during the bird breeding season was moderate to high for moorhens (16–27% of adults and 46–79% of broods) and high for coots (30–51% of adults and 50–86% of broods). 5. Although moorhens seem well adapted to withstand predation by mink, nesting behaviour by coots make them very vulnerable to mink predation. We hypothesize that the persistence of coot populations in areas with high mink density requires immigration from surrounding populations with lower mink impact.

The Great Blue Heron in Kansas

The distribution of and number of nests in the colonies of the great blue heron, Ardea herodias Linnaeus, in Kansas was checked annually from 1952 to 1962 and in 1973 and 1978. These nesting colonies are distributed statewide with heaviest concentrations in the Flint Hills. During dry weather cycles the average number of nests per colony dropped and increased during normal or wet years. The greatest number of nests recorded was in 1978 when there were 3075 nests in 94 colonies. The primary trees used are sycamores in the east and cottonwoods in the west. Life habits of herons during the nesting season were carefully observed and recorded on regular visits. This was accomplished from a blind placed where it would not disturb the birds but enabled observation into 45 nests. Nest construction, mating, incubation and care of young were the main topics observed.