The Availability of Tree Hollows for Use as Nest Sites by White-tailed Black Cockatoos

1979 ◽  
Vol 6 (2) ◽  
pp. 205 ◽  
Author(s):  
DA Saunders

Data on nest hollows were collected from four study areas throughout the range of the short-billed form of the white-tailed black cockatoo, Calyptorhynchus baudinii latirostris, in south Western Australia. Hollows in trees are formed as a result of some destructive agent such as termites or fungi attacking the heartwood of the tree and breaking down the structure of the wood cells. The breaking off of part of the tree provides access to the hollow from the outside, and allows it to be used as a nest site. Throughout their breeding range, white-tailed black cockatoos will nest in any species of eucalypt which has a hollow of suitable size. The aspects of the entrances of hollows are not randomly distributed among compass groups, but the birds' selection of hollows was random. The aspect, depth to the floor and height of the entrance from the ground do not affect the success or failure of the nesting attempt. Female white-tailed black cockatoos searching for and preparing nest hollows chase female conspecifics from an area around their prospective nest tree. They continue this activity until they are incubating; this may result in suitable hollows not being accessible to other females. The rate of loss of hollows was 4.8 and 2.2% at two of the study areas. Hollows are being destroyed by all causes, particularly clearing for agriculture, faster than they are being created. Guidelines for the management of woodland must be drawn up so as to maintain a continuing supply of mature trees and protect hole-nesting species.

2020 ◽  
Vol 13 (3) ◽  
pp. 63-69
Author(s):  
Bo Zhou ◽  
Changzhang Feng ◽  
Wei Liang

The quality of breeding habitat may directly affect the survival and development of progeny. Therefore, the selection of a suitable nest-site is an important factor affecting the reproductive success of birds. The most important reason for a bird’s reproductive failure is nest predation. Predation may cause birds to change their nest-sites and even nest morphology. Here we investigated the nest-site characteristics by long-tailed broadbills ( Psarisomus dalhousiae) in Nonggang, Guangxi, southwestern China. Our results showed that long-tailed broadbills in Nonggang mainly build their nests on power lines (88.5%) and nest-site selection was mainly affected by predation pressure and food resources. At the same time, nest-site concealment was trade-off against predator avoidance. This anti-predator strategy effectively utilizes human infrastructure.


1998 ◽  
Vol 20 (3) ◽  
pp. 377
Author(s):  
M.S. Wood ◽  
R.L. Wallis

The potential for feral Honeybees (Apis mellifera) to competitively exclude Common Brushtail Possums (Trichosurus vulpecula) from tree hollows was examined in the You Yangs Regional Park, Victoria. The characteristics and occupancy of 77 hollow-bearing trees and 250 hollows were recorded in six 2 ha sites and used to compare the extent of overlap in nest site selection between bees and posssums. Colonies of feral A. mellifera occupied 25 % of all hollow-bearing trees and 8 % of useable hollows, yielding a density of 1.66 colonies per ha, the highest recorded so far in Australia. Trichosurus vulpecula utilised 74 % of hollow-bearing trees and 48 % of useable hollows. Nest site characteristics of bees and possums overlapped in several dimensions, especially in the size of tree and height of nest. Relatively few vacant hollows were suitable for T. vulpecula, whereas many were available to Honeybees. Only 35% of bee nests were in hollows unsuitable for possums, indicating a relatively high potential for competition.


1996 ◽  
Vol 74 (8) ◽  
pp. 1394-1401 ◽  
Author(s):  
Susan B. Meek ◽  
Robert M. R. Barclay

We assessed the settlement pattern of colonial Cliff Swallows (Hirundo pyrrhonota) to examine whether they avoid settling near to each other or prefer to nest in close proximity. Male Cliff Swallows occupied and defended nests before females paired with them, and males settled next to other males significantly more often than expected by chance. In contrast to that of males, female settlement was not significantly different from random: females neither preferred nor avoided settling next to other Cliff Swallows, nor did females select old nests on the basis of nest stability. Neither males nor females chose nests in the same order from year to year, suggesting that quality of old nests was not an important factor affecting settlement patterns. Male arrival date is related to quality in some species, but female Cliff Swallows did not select the earliest arriving males. There was also no correlation between the order in which females chose mates and male traits. All nest sites may have offered females an equal probability of success, leading to random settlement with respect to other females, nests, and males.


1982 ◽  
Vol 60 (3) ◽  
pp. 452-459 ◽  
Author(s):  
Richard W. Knapton ◽  
J. Bruce Falls

We analysed several vegetational variables in four populations of White-throated Sparrows (Zonotrichia albicollis) to determine if differences exist between the white-stripe (WS) and tan-stripe (TS) morphs at the level of the macrohabitat (territory) and the microhabitat (nest site). Univariate and discriminant function analyses revealed that trees were farther apart, more light penetrated to the forest floor, and fewer shade-tolerant plants occurred in territories of WS than TS males. There was little difference between females of the morphs in selection of nest sites. The distribution of territories of WS males along the discriminant function axis (macrohabitat analysis) was narrower than that of TS males, and was concentrated toward the "open" habitat end of the axis. The distribution of territories of TS males spanned the length of the axis, from "open" to "dense" habitat. The question why WS male × TS female pairs occupy a relatively narrow range of habitat whereas TS male × WS female pairs occupy a much broader range is discussed.


2005 ◽  
Vol 15 (4) ◽  
pp. 313-326 ◽  
Author(s):  
UTE BRADTER ◽  
SUNDEV GOMBOBAATAR ◽  
CHULUUNBAATAR UUGANBAYAR ◽  
TRACY E. GRAZIA ◽  
KLAUS-MICHAEL EXO

North-eastern Mongolia is an important breeding area for the globally threatened White-naped Crane Grus vipio. We studied reproductive performance and the influence of factors related to livestock grazing on reproduction and nest-site selection of the White-naped Crane population in the Ulz river valley, north-eastern Mongolia in 2000 and 2001. In 2001, 42 territorial pairs were found in 270 km of river basin. Recruitment was 18–22% resulting in 0.5–0.6 juveniles per territorial pair. The years 2000 and 2001 were within a dry period and recruitment might have been below the long-term average. White-naped Crane nests were significantly associated with river basin sections containing shallow water-bodies. The number and extent of shallow water-bodies are likely to be a limiting factor for breeding population size. Nest-sites in water-bodies were selected for high nest concealment, but nests were initiated even when concealing vegetation was not available. Only 26% of nests were >90% concealed suggesting that appropriate cover was often not available. Nest-sites were also selected for low grazing intensity. No correlation was found between hatching or fledging success and nest concealment or grazing intensity. Brood-size of successful pairs was higher if the home range was ungrazed, but further investigations are needed to clarify whether this was caused by absence of livestock grazing or other factors. Both because of internationally important numbers and because of a potentially high reproductive output, the study area is of high importance for the species.


2016 ◽  
Vol 24 (2) ◽  
pp. 32-45
Author(s):  
Gizella Janó ◽  
Zsolt Végvári

Abstract In the present study we aimed to identify factors influencing the spatial distribution of Great Bustard (Otis t. tarda) nests found between 1998 and 2015 in Dévaványa-Ecseg area in Körös-Maros National Park. During the study period covering 17 years, we obtained information on 536 nests, which shows that Great Bustards used the following grassland crop types for breeding: wheat (43.07%), grassland (23.3%), fallow land (14.45%) and alfalfa (7.67%). These nests were found during the following activities: chemical weed control (33.63%), hay-cutting (25.37%), disking (8.55%) and harvesting (7.08%) and other 18 types of activities. To identify the effects of disturbance and environmental factors on the spatial distribution of nests, such as distances to lek sites, roads, settlements and altitude, we formulated generalized linear models. As a result, we found that nest sites were significantly closer to lek sites and farther from human settlements than expected by random sampling. Our results may contribute to the understanding of Great Bustard nest distributions, which can be helpful in nest detection prior to the initiation of disturbing agricultural activities, which is a key issue in the conservation of this bird. This study opens the way to analyse the effects of other environmental factors such as anthropogenic linear objects.


1982 ◽  
Vol 9 (3) ◽  
pp. 541 ◽  
Author(s):  
D. A. Saunders ◽  
G. T. Smith ◽  
I. Rowley

A 15-ha plot of salmon gum woodland contained 241 hollows with an entrance diameter and depth exceeding 90 mm, in 173 trees, the majority (95%) in salmon gums. Occupancy of these hollows during the spring of 1978 was 47%; eight species of bird (six Psittaciformes, one Anseriformes and one Falconiformes) were involved. Galahs, corellas, red-tailed black cockatoos and Port Lincoln parrots were the most numerous hollow-nesting birds in the area; there were differences in the sizes of hollows they used, which were separable on entrance size and on inside diameter of the hollow 0.5 m below the entrance. There was a trend for hollow size to decrease in the order: red-tailed black cockatoos, corellas, galahs and Port Lincoln parrots. Red-tailed black cockatoos nested in more dead trees, or trees which were lower and had smaller canopies, than did the other three species. The woodland contained few young trees, trees were dying rapidly and there was no regeneration. This situation is typical for woodland throughout the agricultural area, and future prospects are discussed.


2007 ◽  
Vol 34 (8) ◽  
pp. 640 ◽  
Author(s):  
Marnie L. Swinburn ◽  
Patricia A. Fleming ◽  
Michael D. Craig ◽  
Andrew H. Grigg ◽  
Mark J. Garkaklis ◽  
...  

Grasstrees (Xanthorrhoea) are an important structural component of many Australian ecosystems and also an important resource for many fauna species. Grasstrees have distinctive morphologies, with a crown of long thin leaves and skirts, the latter of which are accumulated dead leaves; both are incinerated by fire. This study determined the morphological features of Xanthorrhoea preissii, which change in response to fire from 6 months to 21 years post-burn. In addition, using radio-telemetry and spool-tracking, we determined that grasstrees are utilised as foraging and nesting resources for mardos (Antechinus flavipes leucogaster (Gray, 1841), Marsupialia: Dasyuridae). Recently burnt grasstrees (6 months post-burn) appeared not to be used by mardos at all. We found few mardos in these recently burnt sites, and the one individual we managed to track for 126 m utilised only a single grasstree: a 2-m-tall multiple-crowned grasstree that had escaped the fire was used as a nest site. For sites 5 years post-burn, mardos selectively utilised grasstrees with larger crown areas and those with a greater number of crowns compared with a random sample of available trees. At the 14-year post-burn sites, mardos still demonstrated some selection for grasstrees, although no specific single feature could be determined as most significant. We recorded humidity and temperature buffering effects in association with post-burn accumulation of grasstree skirt material and found that even dead grasstree ‘logs’ were an important resource for nests. We conclude that mardos utilise both live and dead grasstrees for foraging and nest sites, possibly owing to the availability of dense cover, a buffered microclimate, and potentially also food resources. Fire-management policies that promote habitat heterogeneity and retain several intact-skirted grasstrees within the landscape are likely to benefit mardos.


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