Nest Height Research Articles

Breeding Biology of Squacco Herons (Ardeola ralloides) in Northern Tunisia

Abstract We studied the reproduction patterns of Squacco Herons, Ardeola ralloides, during 2009–2010. This study was carried out in two colonies located at Ichkeul National Park (37.184992 N, 9.633758 E) and Lebna Dam (36.744161 N, 10.916569 E), in northern Tunisia. We determined the reproductive performance of the species, and investigated the relationship between reproductive parameters and nest characteristics (height and diameter). We registered successful nesting, with mean clutch size of 4.51 ± 0.85 for both years combined. Hatching success was 3.67 ± 1.07 eggs hatched/nest and fledging success reached 3.06 ± 1.28 young/nest. All reproductive parameters varied between years. The diameter and the height of nest had no effect on the clutch size, the initial brood size, or the final brood size at each site. We estimated the body condition index (BCI) and the growth curves of developing nestlings from repeated measurements of body mass, tarsus, head and bill length. The last chicks (rank four) to hatch ...

Nest-location and nest-survival of black-chinned hummingbirds in New Mexico: a comparison between rivers with differing levels of regulation and invasion of nonnative plants

We compared plants used as sites for nests and survival of nests of black-chinned hummingbirds (Archilochus alexandri) along two rivers in New Mexico. Along the free-flowing Gila River which was dominated by native plants, most nests were constructed in boxelder (Acer negundo). Along the flow-restricted Middle Rio Grande which was dominated by nonnative plants, most nests were constructed in nonnative plants such as Russian olive (Elaeagnus angustifolia) and saltcedar (Tamarix). Mean nest height varied among species of plants used as nesting sites but was about 4 m at each study area. Logistic exposure-estimates of survival of nests were considerably higher along the Middle Rio Grande (52%) than the along the Gila River (23%). Survival of nests was influenced by nest height and species of plant used as nesting site, with survival rates of nests greatest at mean heights in Russian olive and saltcedar. Our results highlight considerable variation in nesting characteristics between two study areas and show that subcanopy nest-sites are essential components of productive habitat for this species.

Plasticity in Nest Placement of the Turtle Dove (Streptopelia Turtur): Experimental Evidence from Moroccan Agro-ecosystems

A total of 364 Turtle Dove ( Streptopelia turtur) nests were found in the Tadla irrigated area during the 2006–2009 breeding seasons. Of these, 135 were located in orange orchards, 178 in olive orchards and 51 in olive hedgerows. Gaussian generalised linear modelling was used to model the nest height and the nest–trunk distance according to the characteristics of olive and orange trees in the orchards and hedgerows. Tree height and type of plantings had the strongest effects on both nest height ( R2 = 0.67) and nest–trunk distance ( R2 = 0.48). Overall, the same pattern of Turtle Dove nest height was recorded in the three types of plantings, whereas different patterns were noted for the nest–trunk distance. The results provide evidence of non-random patterns of nest placement in olive and orange agro-ecosystems. This game species exhibits adaptive behavioural plasticity in nest placement and appears to be well-adapted to the olive and orange grove conditions in this region. This high adaptability is beneficial to maintaining the species in these artificial habitats. Additional quantitative studies are needed to improve our understanding on the mechanisms driving the choice of nest placement by Turtle Doves in this agricultural man-made environment.

Landscape and regional context differentially affect nest parasitism and nest predation for Wood Thrush in central Virginia, USA

ABSTRACT Many empirical studies have shown that forest-breeding songbirds, and Neotropical migrants in particular, suffer greater rates of nest predation and nest parasitism in smaller forest patches and in fragmented landscapes. To compare the performance of different metrics of spatial habitat configuration resulting from deforestation, we studied nest predation and nest parasitism rates at 200 Wood Thrush (Hylocichla mustelina) nests in eight forest fragments ranging from 82 to 9,171 ha in central Virginia, USA. We analyzed nest parasitism rates using logistic regression and we analyzed daily nest predation rates under a multistate competing risks design. For both analyses we compared the performance of 16 covariates, 11 of which related to the spatial configuration of habitat (e.g., patch size, distance to edge, percent core forest in proximity to nest) and 5 of which were unrelated to habitat (e.g., year, serial date, nest height). Distance to agriculture gained the greatest support in analyses of ne...

Does the Threat of European Pine Marten (Martes Martes) Predation Influence the Height of Nests Built by Blue Tits (Cyanistes Caeruleus) and Great Tits (Parus Major)?

The major aim of this study was to examine the influence of the European Pine Marten ( Martes martes) predation on the heights of nests of Blue Tits ( Cyanistes caeruleus) and Great Tits ( Parus major) in nestboxes of different security levels. To this end we performed a comparison of nest heights before and after introducing an anti-predator device to two size-types of wooden nestboxes set up in a deciduous forest. Blue Tit and Great Tit nest sizes were influenced by the application of plastic entrance tubes as anti-predator devices that elongated a distance between the entrance and the interior of the nestbox. Nests were taller in nestboxes equipped with anti-predator devices regardless of nestbox size. Nests located in smaller nestboxes were destroyed by Martens more frequently than nests built in bigger nest boxes. Most nest functions in cavity-nesting birds, such as filling the excessive cavity space, maintenance of proper humidity, thermal, light and sanitary conditions for eggs and nestlings, improve with nest sizes. Because, in contrast, the risk of nest predation by martens increases with nest size (height within the nestbox), the nest predation constitute a major factor that constrains cavity-nesting birds in constructing tall nests.

Factors affecting offspring growth and daily nest survival rates in the coastal breedingWesternReefHeron (Egretta gularis) in thePersianGulf

AbstractOffspring growth and nest survival of waterbirds are important and prominent characteristics of their life history. Nestling growth and daily survival rates of the Western Reef HeronEgretta gulariswere studied in Hara Biosphere Reserve, Persian Gulf, Iran. Growth parameters were determined in relation to both age ranking of each nestling within a brood and the brood size using data from known‐age nestlings. Nesting success was modeled based on the information‐theoretic approach implemented by the programMARKto assess the effects of clutch initiation date, nest size and location on daily survival rates of nests. Mean daily growth rate of body mass was 18.06 ± 6.22 g during the first 2 weeks of age and was independent of brood size but was greater in nestlings hatching earlier within the brood. Wing and tarsus growth rate was influenced by both brood size and nestling rank within the brood, but culmen growth was independent of both factors. Earlier hatched nestlings grew faster than those hatched later. Growth of all morphometric parameters followed the Logistic growth curve model except for wing chord, which fitted the Gompertz growth model. Nest size and nest height above the ground were the most important predictors of nest survival (ωi = 0.79 and ωi = 0.69, respectively), with survival among Western Reef Heron nests improving as the nest size and nest height increased. This study shows the importance of temporal and spatial variables for breeding ecology of a common but little‐known breeding heron in coastal areas of Persian Gulf.

Occurrence of the medicinal leech (Hirudo medicinalis) in birds’ nests

Occurrence and breeding of Hirudo medicinalis were recorded in birds’ nests in the fishing ponds and water bodies used extensively by anglers in south-eastern Poland, in 4 of 11 studied bird species (Circus aeruginosus, Fulica atra, Cygnus olor, Chroicocephalus ridibundus). Factors important for the distribution and density of this leech were: nest height, pH of the water and oxygen concentration in the water inside the nests, the body-length of the nesting birds. Our data show that (1) H. medicinalis chooses nests as habitats that are safe in water bodies rich in predators (particularly fish) and provide stable feeding conditions; (2) fishing ponds and other water bodies used extensively by anglers in a landscape modified by human pressure can be an important secondary habitat for the medicinal leech. As the nesting activity of some aquatic birds apparently favors the occurrence of H. medicinalis, active protection of aquatic birds and creating sites appropriate for their breeding may be an indirect way for the conservation of the leech in such areas.

Phenotypic plasticity in nest departure calls: weighing costs and benefits

In birds, male song has been extensively studied, but female vocalizations have received little attention. Females of several North American species produce a unique vocalization, the nest departure call (NDC), upon leaving nests. Producing NDCs has costs due to acoustical properties that make nests easy to locate by predators. Thus, NDCs must also have benefits that balance or outweigh costs, and females should modulate call production as costs and benefits change. We explored whether female song sparrows, Melospiza melodia , adjust calling rate to reflect differential costs and benefits of calling induced by male presence, male quality (measured by body mass and song complexity), nest predator presence and nest height. Results suggest that calls benefit females by promoting male nest guarding and that females display adaptive plasticity in call production. Specifically, calling rate increased when the male was present, and male nest guarding increased when females gave an NDC. Females called less in the presence of a model nest predator, probably because the perceived costs of predator attraction outweighed the benefits of male recruitment. Conversely, females with heavier mates called more, perhaps because the efficacy of male nest guarding increases with mass. In addition, females called more from elevated nests in the presence of the predator and decreased calling later in the day. Male song complexity failed to predict calling rate, suggesting that this sexually selected trait does not reflect direct benefits gained by producing an NDC. Plasticity in calling probably exists because context-appropriate communication elevates fitness, whereas contextual mistakes in the decision to communicate result in fitness declines. • We examined the function of, and plasticity in, nest departure calls of female song sparrows. • Our results suggest that nest departure calls function to promote male nest guarding. • Females appear to balance costs and benefits when plastically adjusting calling rate. • Females called more when the male was present, increasing benefits of calling. • Females called less in the presence of a predator, reducing costs of calling.

Variability of daily nest survival and breeding success in relation to characteristics of Eurasian magpie (Pica pica) nests

Size and structure of birds’ nests can arise from evolutionary trade-offs between benefits, such as insulation from unfavourable conditions, maintenance of eggs or chicks, security against predation, and costs, such as energy spent in construction of the nest and the risk of predation in more visible nests. The relationships between nest characteristics and breeding success and survival probabilities of Eurasian magpie (Pica pica) eggs and nestlings were studied in Baghbadaran, central Iran during the 2008 and 2010 breeding seasons. Nesting success was modelled to assess the relationships between nest parameters and the probability of daily nest survival. Mean clutch and brood size, hatching, fledging and breeding success did not vary significantly between the two years. Mean internal diameter, external diameter, distance to feeding location and distance to open areas varied significantly between the two study years. Daily nest survival rate for both years (2008 and 2010) was 0.98 ± 0.002. Nest size and status of nests, defined as old or newly established nests, were the best factors predicting probabilities of nest survival. Nests with small internal diameters had higher overall nest productivity. Nest height was positively correlated with both fledging success and breeding success. Our results agree with previous findings that have shown that magpie pairs with large nests provided their nestlings with higher quality food compared with pairs with smaller nests and so nest size was an indicator of parental ability. Nest height is also recognized as an important determinant of nest predation, mostly because it may affect nest detectability and accessibility.

Vertical nest stratification of four heron species in southern Brazil

Herons generally breed in mixed flocks and their nests are made in shrub wetlands and on islands. Waterbirds can select different tree species in the heronries which can influence the vertical stratification of the heron nests. The aim of the present study was to determine the vertical nest stratification among four Ardeidae species in heronries in southern Brazil. The study was carried out during four breeding seasons between 2004 and 2009. No significant species-specific difference in mean nest height was observed between the three heronries. However, there was some variation in nest heights per species in the four years of the study and among the heron species. Nest height was correlated with the body size of the heron species. The smaller species, Bubulcus ibis, Egretta thula, and Nycticorax nycticorax, occupied mainly the lower stratum and the largest, Ardea alba, the higher stratum. The colonist species B. ibis did not show a clear preference, occupying both Mimosa bimucronata and Cephalanthus glabratus for nest building, while the other three herons selected mainly M. bimucronata if the two tree species were available.

Status of the eastern imperial eagle (Aquila heliaca) in the Czech Republic – 2013 update, ringing results and new findings

Abstract Although unconfirmed reports on the breeding of the eastern imperial eagle exist from as early as in 1 920s, the first confirmed breeding only took place in 1 998. Since then, 1-5 pairs have bred annually, chiefly in the South Moravia region (the Breclav, Znojmo and the Brno-venkov districts). Out of 37 breeding attempts, 26 (i.e. 70%) were successful, with 48 young reared. The paper summarizes some characteristics of the breeding biology (productivity, breeding losses, nesting tree species, nest height, nest turnover, minimum convex polygon of the nests [nesting trees] built by individual pairs) as well as ringing recoveries. Out of 42 ringed chicks, 39 fledged successfully and produced 3 recoveries (Slovakia - 2, Austria - 1 ). Three foreign ringed birds were also sighted in the Czech Republic. The most interesting case is the breeding of a 1 9-year-old female born in eastern Slovakia (distance 336 km), found via a photo of the ring (V. Gahura, 201 3).

Nest site use by the small Japanese field mouse: possibility of nest height change in the presence of the Siberian flying squirrel

Nest site use by the small Japanese field mouse: possibility of nest height change in the presence of the Siberian flying squirrel

Nest dimensions and nest sites of the harvest mouse (Micromys minutusPallas, 1771) from Slovakia: a case study from field margins

Little is known on the nesting habitat requirements of the harvest mouse (Micromys minutus) on an arable landscape. A total of 230 summer nests were found over the years 2010–2012 on the branches of shrubs and herbaceous species (Prunus spinosa, Phalaris arundinacea, Rubus fruticosus, Urtica dioica, Tanacetum vulgare, Cornus sanguineus, and Carpinus betulus), and two nests were found directly on the ground in vegetation. The results confirmed that the main nest supporting species in field margins were: P. spinosa, R. fruticosus, and Ph. arundinacea. The results proved that nests had a relatively large interval of values. Length of nests was 4,5–14,0 (mean ± SD: 6,6 ± 1,2) cm, width of nests 4,0–10,0 (6,0 ± 0,9) cm, height of nests 4,0–10,0 (6,0 ± 0,9) cm, and volume of nests 46,1–523,6 (130,5 ± 66,1) cm3. In most cases nests were circle (56,1%) or oval (43,9%) structures. Moreover, the analysis confirmed a positive correlation between the distance of the nest from the ground and from the top of the plant ...

Nest survival and breeding biology of the Puerto Rican Bullfinch (Loxigilla portoricensis) in southwestern Puerto Rico

Abstract Breeding biology information, including nest survival estimates, are lacking for many nesting species in Puerto Rico. We studied the endemic Puerto Rican Bullfinch (Loxigilla portoricensis), and modeled daily nest survival to better understand the effects of several factors on daily nest survival. In 2009 and 2010 we monitored 37 bullfinch nests at two sites in southwestern Puerto Rico. Predation was the most important cause of nest failure. Ten nest survival models received approximately equal support. No temporal trends in nest survival were supported over others. Results suggested that available fruit is important for successful nesting, increased precipitation is related to higher nest survival, nest survival varied by site, and increased nest height is related to lower nest survival in bullfinches. Under the top model, daily nest survival rates for each site and nest stage ranged from 0.83–0.86% in 2009 and 0.80–0.93% in 2010. This information on nest survival and factors that influence it i...

Population status, nesting habitat selection and conservation threats of lesser adjutant stork (Leptoptilos javanicus) in the eastern lowlands of Nepal

Aim This research examines the status of distribution, nesting habitat selection and conservation threats of lesser adjutant storks. Location Eastern Nepal Materials and Methods Direct observation along line transects method was used to determine population status, distribution and nesting habitat preference of storks in different habitats of the study area. Questionnaire surveys to local people drawn randomly were used to study the socio-cultural dimensions of lesser adjutant storks conservation. Key findings There were a total of 98 individuals in pre-breeding and 240 individuals of lesser adjutant stork in post-breeding periods (94 chicks and 146 adults) in the study area. On average, there were 1.29 chicks per nest. Bombax ceiba and Adina cordifolia were found to be the most preferred nesting trees for lesser adjutant storks. Habitat preference of lesser adjutant storks revealed that colonies were more likely to occur in farmlands and swamps. All the nests of lesser adjutant storks were found on trees above 30 m height, the average tree height was 42.5 ± 6.8 m and the average nest height was 34.4 ± 4.3 m. Questionnaire surveys revealed that people were not aware about conservation of lesser adjutant storks. More than 80% of respondents (n=145) opined that forest destruction was the most serious threat to storks followed by human disturbance (79%), poaching (73%), pesticide use (52%), and urbanization/industrialization (43%). Conservation implications Protection of nesting tree species such as Bombax ceiba and Adina cordifolia should be given a high priority for the conservation of storks in the eastern Nepal. Conservation education programs to control excessive pesticides in the rice fields should also be carried out in the region. DOI: http://dx.doi.org/10.3126/cs.v1i1.8581 Conservation Science 2013 1(1), 27-35

Bald Eagle Nesting Habitats in the Upper Mississippi River National Wildlife and Fish Refuge

AbstractThis study examined habitat variables associated with 53 active bald eagle Haliaeetus leucocephalus nest sites in the Winona District of the Upper Mississippi River National Wildlife and Fish Refuge, Minnesota and Wisconsin. The Refuge is the most heavily visited refuge in the United States, where breeding eagle populations have been increasing dramatically. During February–April 2009, nest trees were identified and measured, nest heights were determined, distances to nearest water bodies were assessed, and forest inventories were conducted for the standing timber surrounding the nest trees. Nest densities and spacing were assessed within each navigation pool, and land cover types were examined within 100- and 1,000-m radii around known eagle nest sites and random points within the Refuge. Ninety-three percent of nest sites had supercanopy eastern cottonwoods Populus deltoides and silver maples Acer saccharinum as the nest trees. Potential human disturbances from highways, railroads, and commercial barge and recreational boat traffic were present within 400 m of 90% of known nest sites. Eagle nest sites were located an average of 1.52 km from the next nearest nest, with nest densities ranging from 0.32 to 9.72 nests/100 km2 among the four navigation pools of the Winona District. Land cover types around known nest sites and random points differed significantly at both 100- and 1,000 m scales, with wet forest and open water significantly more abundant and agricultural and developed lands significantly less abundant than around randomly selected points. Successful nests that fledged at least one young were spaced significantly further away from other active nests and were located in areas with lower tree density than were unsuccessful nests. Floodplain-nesting bald eagles tended to select the tallest, dominant trees for nest sites, placing nests near the height of the surrounding canopy. Human presence within the Refuge does not appear to be limiting the expansion of nesting bald eagles in this riverine habitat.

Nest and nest site characteristics of the Great Crested Grebe (Podiceps cristatus) on intensively managed fishponds: an example from Bohemia

Selected data of nest biology of the Great Crested Grebe (Podiceps cristatus) (Aves Podicipediformes) in specific fishpond conditions in the Protected Landscape Area and Biosphere Reserve Třeboňsko (Czech Republic) were analysed. An interdependence of dimensions of the nesting dent was found: the wider the dent, the deeper it was. A positive correlation was also found between the total nest height and the nest height above water level. Differences in most measured characteristics in relation to the number of eggs were not found (the positive correlation with the width and depth of the nest dent only). A positive correlation between the distance from the nearest nest and the water depth was found. The results also suggest a relationship between the distance of the nearest nest and the distance from the free water level, as well as between the water depth near the nest and the nest distance from the free water level. Nests near the shore were denser than nests on the free water level. The mutual distance of the nearest nests was linked to the location of vegetation and water depth. In the case of group nesting of more pairs, no inclination to form spatial clusters or regularity in deployment was found. These observations confirmed the ability of Great Crested Grebe to adapt to the specific environmental conditions of intensively managed fishponds including higher nesting density.

Breeding biology of coppersmith barbet, Megalaima haemacephala (Müller, 1776)

Breeding biology of the Coppersmith barbet, Megalaima haemacephala (Müller, 1776) was carried out between February, 2006 and January, 2007 at Sharawardy Uddyan, Ramna Park, Curzon Hall and National Botanical Garden. The breeding season started from December and ended in June. In total 20 nests were observed, of which 10 nests were studied in details in four study areas. The coppersmith barbet mostly preferred to make holes on the branches of koroi (Albizzia procera) for nesting. Egg laying started on 15th February in the study areas. Average height of nests from the ground was 9.7m and average depth and diameter of the holes was 29.20cm and 4.46cm respectively. New holes were constructed yearly or the old one was reused. Both the sexes took part in incubation of eggs, brooding and feeding to the nestlings. A total of 30 eggs were laid in 10 nests. Clutch size varied from 2 – 4 eggs (average: 3 eggs). Among them, 20 (66.67%) eggs were hatched and the rest 10 (33.33%) were unhatched and lost. Average incubation period was 14 days. The male and the female incubated the eggs for an average of 27.44 minutes/ hours and 32.56 minutes/ hours, respectively. Average number of nestlings (brood size) per nest was 2. Out of 20 nestlings, 16 left their nests successively. The breeding success was 53.33% in relation to the number of eggs laid and 80% in relation to nestlings hatched. The average weight of eggs and nestlings was 3.59g and 9.33g, respectively. The main causes of loss of the eggs and nestlings were human interference, predation and ectoparasitic infections. Insects and fruits were fed to the nestlings by their parents.DOI: http://dx.doi.org/10.3329/ujzru.v31i0.15397Univ. j. zool. Rajshahi Univ. Vol. 31, 2012 pp. 31-34

Estrutura do ninho, incubação e eclosão de Phyllomedusa trinitatis (Anura: Hylidae)

New findings on nesting and hatching are reported for the leaf-nesting tree frog Phyllomedusa trinitatis. Nest height and leaf cover (one or many leaves; well or poorly covered) were very variable. Contrary to a previous report, eggless jelly capsules were scattered amongst the eggs, with substantial jelly plugs located above and below the egg clutch. Plugs were composed of capsules embedded in a matrix of somewhat different composition. The upper plug acted as a barrier to water entry. Contrary to previous reports, isolated eggs could develop in aquatic media, the later stage on entry the better: aeration and salt composition of the water influenced this ability. Egg clutches developed equally well whether the covering leaves were alive or dead. Single eggs incubated in water hatched prematurely; when placed in water, eggs near hatching stage hatched within a short time; such eggs on a dry or damp substrate did not hatch till much later. The hatching of any embryo in a group appeared to act as a stimulus to neighbours to hatch. Observations on nests with the covering leaves replaced by clingfilm showed that emergence is preceded by a lengthy period of hatching behavior, with individuals hatching, wriggling and stimulating larger and larger groups to hatch, and releasing a frothy fluid which leads to the dissolution of the lower jelly plug and emergence of the hatchlings. Contrary to a previous report, hatching gland cells were observable on the laterodorsal surface of the head. When hatchlings emerged from the nest, they were mostly at Gosner stage 25 with gills fully resorbed. When earlier embryos were induced to hatch, they rapidly shortened their external gills. These findings are discussed in comparison with observations on the related genus Agalychnis.

Ecology and breeding biology of the pond heron, Ardeola grayii (Sykes, 1832) and its conservation aspects

Studies on ecology and breeding biology of the pond heron, Ardeola grayii was conducted from January to June, 2010 in Kalairpur Assim Union, Fulbaria under Mymensingh district. The breeding season of this bird ranged from February to June. The peak period for nesting was March. The pond heron choose the nesting site surrounding the human settlements near the pond and other water bodies. This species took 7 to 14 days to complete nest with an average of 10.8 days. The height of nest varied from 5.2 m to 10.9 m with an average of 7.82 m. The main nesting trees were bamboo (Bambusa longispiculata) and mango (Mangifera indica). Nesting materials were chiefly small sticks of mango, tamarind (Tamarindus indica), bel (Aegle marmelos) and leaves of bamboos. The clutch size varied from 3 to 4 eggs with an average of 3.7 eggs. The incubation period varied from 19 to 23 days with an average of 20.73 days. The hatching success was 90% in relation to the number of eggs laid. The fledging period of young varied from 25 to 29 days with an average of 26.73 days. Young individuals left the nest after 3 to 4 weeks. Results of this study indicate that the pond heron can breed successfully for their survival if indigenous plants trees are available to build their nest. So Government should make immediately an integrated conservation plan to protect this bird with the co-operation of national and international organizations. DOI: http://dx.doi.org/10.3329/jasbs.v38i1.15325 J. Asiat. Soc. Bangladesh, Sci. 38(1): 99-109, June 2012