The role of body size in nest-site selection by secondary cavity-nesting birds in a subtropical Chaco forest

Most bird species that nest in tree cavities globally occur in diverse assemblages in little-studied tropical and subtropical forests which have high rates of habitat loss. Conservation of these communities will require an understanding of how species traits, such as body size, influence nest-site selection. We examined patterns of nest-site selection of secondary cavity-nesting birds at the nest patch, tree and cavity scale, and investigated how these patterns are influenced by body size. Using conditional logistic regression, we compared characteristics of 155 nest tree cavities paired with 155 unused tree cavities in quebracho Schinopsis balansae forests in Chaco National Park, Argentina (2016–2018). The odds of a cavity being used for nesting increased with its depth and height above ground, decreased with entrance size, and were greater for dead trees than live. Small-bodied (13–90 g) species used floor diameters in proportion to availability, but medium- (150–200 g) and large-bodied (400–700 g) species selected cavities with larger floors. Model selection indicated that characteristics at the nest patch scale (canopy cover, tree density) had little effect on nest-site selection when cavity-scale variables were included. Cavity floor diameter, entrance size, cavity height and tree diameter (but not cavity depth) increased with body mass, and larger bird species more often used live trees. Two tree species proved to be key for the community: large and medium-sized birds used almost exclusively large live Schinopsis balansae, whereas small birds used live and dead Prosopis spp. in a proportion greater than its availability. Small birds could be differentiated according to species-specific cavity characteristics, but medium and large species overlapped considerably with one another. Although body mass explained much of the overall variation in tree and cavity characteristics between small and medium/large species, several small-bodied species consistently used cavities outside of the expected characteristics for their body size, suggesting that other natural history traits may play important roles in nest-site selection by small-bodied birds. To retain the full suite of secondary cavity-nesters in species-rich tropical and subtropical forests, it is necessary to conserve a diversity of trees and cavities that meet the full range of nesting requirements of these trait-diverse communities.     

郑州郊区崖沙燕(Riparia riparia)的巢址选择

2014年3—8月,采用样方法对分布于河南省郑州市郊区的4处崖沙燕(Riparia riparia Linnaeus 1758)营巢地的13个生境因子进行了调查,测定了巢址样方和对照样方各160组数据,并利用Mann-Whitney U检验对这些数据的显著水平进行了检验;最后采用逐步判别分析(stepwise discriminate analysis)方法确定影响崖沙燕巢址选择的主要生态因子,并建立了标准化的典则判别函数。结果表明,1)崖沙燕洞巢的洞口横径(8.46±0.79)cm,纵径(8.30±0.79)cm,巢洞深(87.80±11.97)cm,巢室长径(11.25±1.33)cm,短径(10.43±1.33)cm,巢室高(9.99±1.33)cm;2)巢址样方与对照样方在植被均高、植被密度、坡位、坡度、崖高、崖长、崖龄及干扰度等8个方面差异达到显著水平,崖沙燕偏好选择的洞巢周围植被较高(97.24±8.42)cm,植被密度较大(64.34±7.15)株/m~2,坡度较大(83.78±0.35)°、上坡位(1.41±0.04)、崖较高处(7.54±0.13)m、崖壁较长(51.18±3.54)m、崖龄较短(2.41±0.05)月及人类干扰较低(1.94±0.06);3)逐步判别分析结果表明,影响崖沙燕营巢地选择的主要生境因子是坡位、崖龄和干扰度,标准化的典则判别函数为y=0.753×坡位+0.681×崖龄+0.288×干扰度。建议在城市化建设过程中针对崖沙燕的巢址选择特性建立合理的保护措施。     

震旦鸦雀在镶嵌型芦苇收割生境中的巢址选择

大规模的芦苇收割会对在该生境中繁殖的鸟类产生严重影响。为降低芦苇收割对鸟类繁殖的负面影响,许多地区的湿地管理者逐渐采用了镶嵌型的芦苇收割方式。但是,这种新的芦苇管理方式对鸟类繁殖期生境选择的作用机理尚不清楚。震旦鸦雀是一种主要分布在我国东部、完全依赖芦苇生境而生存的珍稀鸟类,已被IUCN定为全球性近危物种。大规模的芦苇收割导致其适宜生境丧失,被认为是该物种面临的一个主要威胁。选择山东黄河三角洲国家级自然保护区为研究地区,采用AIC信息准则法,从巢址微生境、巢域斑块和全模型3个水平上对可能影响震旦鸦雀巢址选择的生境因子进行了逻辑斯蒂回归分析,并重点探讨芦苇镶嵌收割对其巢址选择的影响以及不同水平的相互效应。结果发现,震旦鸦雀的巢址选择受巢址微生境和巢域斑块尺度双重水平的影响,但巢址微生境因子的影响要大于巢域斑块因子。在巢址微生境水平上,影响震旦鸦雀巢址选择的因素有:1.5—2.5 m旧芦苇的密度、2.5 m以上新芦苇的密度、香蒲密度和巢的可见度;在巢域斑块水平上,影响因素包括芦苇生境类型、旧芦苇斑块面积的比例和植被盖度;在综合模型中,影响因素有1.5—2.5 m旧芦苇的密度、2.5 m以上新芦苇的密度、香蒲密度、巢的可见度和植被盖度。综上,震旦鸦雀倾向于在植被盖度较高、具有一定比例(18.3%)旧芦苇面积、1.5—2.5 m旧芦苇密度较高、可见度较低的生境斑块中筑巢。研究中,78.7%(n=141)的震旦鸦雀将巢筑在新旧芦苇混合的微生境中,其中36.9%的巢址附近旧芦苇的比例在一半以上;53.2%(n=111)的巢筑于新、旧两种芦苇茎秆之上,22.3%的巢的支撑芦苇中旧芦苇所占比例在一半以上。研究结果表明,旧芦苇在震旦鸦雀巢址选择和筑巢过程中发挥了重要作用。由于大范围的芦苇收割在微生境水平上可降低1.5—2.5 m旧芦苇的密度,在巢域斑块尺度上可降低旧芦苇斑块面积的比例,因此建议,在震旦鸦雀的繁殖地,未来的芦苇收割应采用镶嵌收割的形式,并至少应保留面积在20%以上的结构较好的旧芦苇斑块,以供震旦鸦雀选择巢址和繁衍后代。     

Nest-site selection and predation in Savi's Warblers Locustella luscinioides

Capsule Savi's Warblers preferred sites dominated by high and dense Juncus and Rubus with thick litter, and avoided pure reeds; predation was higher in sites with less litter.

Aim To describe nest-site selection and identify which habitat and nest features influence predation risk.

Methods Comparisons were made between habitat characteristics measured at nest-sites and random points, and between predated and successful nests.

Results Total vegetation cover, litter thickness, habitat type, undergrowth height and undergrowth cover, which were higher or denser at nest-sites, were the most important variables influencing the distribution of Savi's Warbler nests. Nests were most often predated in sites with low litter thickness.

Conclusion Savi's Warblers are dependent on the presence of dense low vegetation and litter for nesting, which should be maintained close to or within reed-beds for their benefit.     

福建漳江口红树林鹭科鸟类巢址选择

2011年4～5月、2012年4～5月,采用样线调查和样方调查相结合的方法对福建漳江口红树林国家级自然保护区内鹭科鸟类巢址与影响其选择的因子进行研究.t-检验结果显示,红树基径、盖度、距地面平均高度、植株密度及秋茄比5个参数在巢区样方(n=23)与对照样方(n=37)之间存在显著差异(P＜0.05),桐花比、距道路距离、距村庄距离与距池塘距离4个参数存在极其显著差异(P＜0.01).主成分分析表明,植被结构和干扰条件是影响鹭科鸟类巢址选择的主要因子,植被结构不仅能够影响鹭科鸟类群落结构,还受到鹭科鸟类集群繁殖影响.     

Nest-site selection and its impact on breeding success of the Lesser Kestrel,Falco naumanni,in the North of Iran (Aves: Falconiformes)

The Lesser Kestrel (Falco naumanni) is a small migratory falcon which nests coloni- ally on inland cliffs and ruined buildings. Bandar Turkman city holds one of the most important breeding colonies in Iran. It nests in holes in roofs, walls or on ledges of buildings throughout of the city. We tried to find out whether there is a relationship between nest-site selection and breeding success. Although height from the ground is the most important factor in nest-site selection by F. naumanni, height from the floor and distance to the nearest neighbour are other main factors which affect breeding success. This could be the result of accessibility by human and natural predators such as domestic cats which threaten nests. The number of possible nest-sites in the study area is limited as many old, ruined buildings are being replaced by new construc- tions; this colonially breeding bird species therefore suffers from a lack of highly suitable nest-sites and this directly affect breeding success.     

Applying structure-from-motion habitat reconstruction and GIS terrain analysis to test hypotheses about nest-site selection by shorebirds

Habitat variables related to vegetation type and structure are routinely identified as important components of nest-site selection for birds. For ground-nesting birds, small-scale (< 0.5 m) microtopography may also play a role in nest-site selection through its effects on nest concealment and microclimate. Manual measurements of microtopography are challenging, time-consuming, and subject to user error. Ultrahigh-density point clouds generated using structure-from-motion (SfM) algorithms and photomosaics captured during Unmanned Aerial Vehicle (UAV) surveys can potentially provide detailed topographical measurements with less error. We used multiple indices of surface roughness to examine the effect of microtopography on nest site selection by White-rumped Sandpipers (Calidris fuscicollis) at East Bay Migratory Bird Sanctuary, Nunavut, Canada. We measured microtopography manually using the relative height index within a 1-m radius of used and unused sites. We generated three digital indices of surface roughness for 1-m and 5-m scales around nests and unused sites, including standard deviation of slope, slope variability, and 2D:3D area ratio. We compared the digital indices of used and unused sites at both spatial scales. Relative height of nearby hummocks was significantly lower at nests than at unused sites, indicating selection for flatter sites. Similarly, two of three digitally calculated terrain roughness indices were significantly lower at nests than unused sites at both the 1-m and 5-m scales. The 2D:3D ratio did not differ between nests and unused sites. Manual and UAV-derived measures were significantly correlated, but with substantial unexplained variation (Pearson’s r = 0.35–0.46). Our results suggest that White-rumped Sandpipers select nest sites in areas with low terrain roughness, potentially to increase their field of view to monitor approaching predators. We also demonstrate the applicability of SfM habitat reconstruction for testing hypotheses of small-scale habitat variables that may be impossible to study using traditional methods.     

THE AVIAN ECOLOGY OF A TUSSOCK ISLAND IN THE FALKLAND ISLANDS

In the windswept and treeless Falkland Islands, the natural vegetation has been seriously depleted by two centuries of extractive farming. One habitat—mature Tussock-grass—is of vital importance to the resident birds, and those Tussock-covered islands that remain in a nearly natural state can support a far greater density and variety of bird species than any areas on the mainland.
Kidney Island maintains a diverse avian fauna because it offers abundant cover, nest-sites, nest materials and food. In and around the dense mature Tussock-grass which covers about 90% of the surface, 28 bird species nest on the island; 18 of them occupy one or other of the six minor habitats which can be distinguished in the Tussock-grass. The nest-sites and interrelationships of these breeding species are described.     

Flexible nest-site selection under anthropogenic habitat change in an Afrotropical understorey insectivore

Human activities impact upon natural habitats used by birds for breeding and foraging, and lead to changes in the composition and spatial distribution of predator communities, mainly through loss, fragmentation and disturbance of formerly pristine habitat. Yet possible fitness consequences of such changes through impacts on bird nest-site selection remain poorly known. Here we study nest-site selection and reproductive success of Placid Greenbuls Phyllastrephus placidus in the Taita Hills, southeast Kenya. We show that habitat features associated with nest-site selection by this insectivorous, open-cup-nesting bird species vary among forest fragments that are exposed to different levels of habitat disturbance. Such differences in sites selected for breeding result from a plastic response to fragment-specific conditions or may be driven by fragment-specific variation in the distribution and availability of certain habitat features. Given the overall high nest predation rates in our study area, we expected variation in nest-site selection to correlate with reproductive success and nestling condition, but detected no such relationship. Because predator density and nest predation rates may vary strongly in space and time, a better understanding of spatio-temporal variation in predator communities is needed to assess the possible adaptive value of nest-site selection strategies for reducing the high predation rates that are typical for this and many other open-cup-nesting tropical passerines.     

白尾地鸦的巢址选择

2017年4和5月,在位于新疆塔克拉玛干沙漠南缘的和田地区民丰县对白尾地鸦（Podoces bidduphi）的巢址选择进行研究。共记录白尾地鸦巢12个,测量了巢参数,用Mann-Whitney U检验分析巢样方与对照样方的差异,用主成分法分析影响白尾地鸦巢址选择的主要因子。结果显示：1）白尾地鸦巢多筑于绿洲边缘的柽柳（Tamarix）灌丛,巢距地面高（109.1 ± 13.2）cm,巢深（8.5 ± 0.5）cm,巢厚（3.8 ± 0.4）cm,内径（13.9 ± 0.9）cm,外径（21.6 ± 1.3）cm;2）巢样方的植被物种数和植被盖度远高于对照样方;3）影响白尾地鸦巢址选择的主要因素为植被物种数及干扰,其中干扰主要指距道路以及距居民点的距离。综上所述,白尾地鸦的巢址选择受食物等生存需求和躲避干扰等安全因素的双重影响,是生存与繁殖权衡的结果。     

四川南充市区珠颈斑鸠的繁殖生态学和巢址选择

2002年11月~2004年4月在四川省南充市区内对珠颈斑鸠(Streptopelia chinensis)繁殖生态和巢址选择进行了研究。结果表明:珠颈斑鸠3月初开始求偶交配,求偶行为复杂,有“婚飞”行为;雌雄参与筑巢,营巢期7~8 d。影响巢址选择的主要因素有6种:栖位与巢周隐蔽因子、巢下隐蔽因子、光照因子、人为活动因子、食物因子和营巢树因子;窝卵数2枚,雌雄轮流孵卵,孵卵期17~18 d,孵化率86.67%;雌雄均参与育雏,育雏期18~20 d,雏离巢率73.08%,繁殖生产力1.82,种群育雏高峰期为7月和8月中上旬。     

Nest location, clutch size and nest success in the Scarlet Ibis Eudocimus ruber

Breeding success and nest-site characteristics were studied during the 1996–1997 breeding season in a colony of Scarlet Ibises Eudocimus ruber in south-eastern Brazil to test the hypothesis that nest-site characteristics and clutch size affect nest success. Two nesting pulses produced young, the earlier being more successful. Predation accounted for most failures during the first pulse, wind destruction during the second. A third pulse with few nests produced no young. Adult Ibises abandoned nests when they lost sight of other incubating birds. Logistic regression analysis indicated that nest success during the first pulse was positively related to clutch size, number of nests in the nest tree and in the nearest tree, and negatively to the distance to the nearest neighbour. During the second pulse there were significant negative associations between success, nest height and distance to the fourth nearest nest, and a positive association between success and nest cover. The results agree with the 'selfish herd' hypothesis, indicating that nest aggregation may increase breeding success, but the nest-site characteristics affecting success can differ over the course of one breeding season.     

An ecological risk assessment for the impacts of offshore wind farms on birds in Australia

An ecological risk assessment, based on life-history and behavioural attributes of 273 bird taxa, was used to identify which of those taxa are at high risk from negative interactions with offshore wind farms in Australia. The marine area of Australia was divided by state/territory boundaries perpendicular to the coast into eight regions, with Western Australia further divided into north and south, and a Bass Strait region bounded by the Victoria coast and the north coast of Tasmania. These regions were subdivided into coastal, inshore and offshore sub-regions and a risk summary for all bird taxa occurring in each of these sub-regions produced. In coastal and inshore sub-regions of Bass Strait, South Australia and Tasmania, the species with the highest risk scores were Orange-bellied Parrot Neophema chrysogaster, Furneaux White-fronted Tern Sterna striata incerta, Swift Parrot Lathamus discolor, Shy Albatross Thalassarche cauta, Far Eastern Curlew Numenius madagascariensis and Anadyr Bar-tailed Godwit Limosa lapponica anadyrensis. In offshore sub-regions in southern Australia, the highest risk species were all albatrosses, comprising Northern Royal Diomedea sanfordi, Eastern Antipodean D. antipodensis antipodensis, Gibson's D. antipodensis gibsoni, Wandering D. exulans, Amsterdam D. amsterdamensis and Grey-headed Albatross T. chrysostoma. Compared to onshore installations, there are logistical challenges to quantifying the potential and realized impacts of offshore wind farms that require different approaches to data collection and analyses. The extensive development of offshore wind farms in the Northern Hemisphere provides examples of best and emerging approaches to quantify and mitigate negative impacts of offshore wind farms that can be applied in an Australian context. Despite differences in the species involved, the same approaches to identifying high-risk species and to the monitoring and mitigation of negative impacts should be applied in a coordinated, regional-scale approach to the development of offshore wind farms in Australia.     

Experimental Study of Nest-site Selection in the Biscutate Swift (Streptoprocne biscutata, Aves: Apodidae) in Southern Brazil

Biscutate swift Streptoprocne biscutata nests are usually built on protected rocky cliff walls. Birds often renest at the same location. Remains of previous nests may offer information about potential nests and quality of nest-sites. Here, we experimentally study nest-site selection to test the hypothesis that information from previous nests is used in current nest-site selection. We placed old nest material at artificial nest-sites to test whether new nest-sites are chosen based on the presence of nesting material. We also tested whether the use of natural nest-sites is influenced by nesting material by creating two types of natural sites: previously used natural nest-sites with vestiges of old nests removed and never used natural nest-sites to which vestiges of old nests were added. In the first experiment, in 139 nest-use opportunities, 16 artificial nest-sites were used, all of which included vestiges. In the second experiment, in 91 nest-use opportunities, four nests were in previously unused but natural locations to which vestiges had been added, 22 nests were in previously used sites without vestiges, and the remaining 65 nests remained unused. Two processes are apparently in action: first, prior experience and memory; second, vestiges indicate where nesting has occurred, possibly useful for first breeding, or for imperfect memory. Previous nesting information may explain why swifts use nesting locations for many years and why new nesting colonies seldom form. This transmission of information suggests that swifts tend to be conservative and nest where previous nesting has occurred.     

利用天然树洞繁殖的五种鸟的巢位特征及繁殖成功率

对吉林省左家自然保护区次生阔叶林中的大山雀 ( Parusmajor)、沼泽山雀 ( Paruspalustris)、普通跓( Sitta europacea)、白眉姬? ( Ficedula zanthopygia)和灰椋鸟 ( Sturnus cineraceus) 5种利用天然树洞繁殖的次级洞巢鸟进行了巢位选择和繁殖成功率研究。本研究中共发现 1 41巢。五种鸟对树洞类型的选择存在种间差异 ,普通跓不利用裂洞 ,沼泽山雀不利用啄洞 ,其它 3种鸟对 3种洞均有利用 ,但有一定的倾向性。对 5种鸟 9个巢位变量的比较中 ,只有洞口方向差异不显著 ( p >0 .0 5 ) ,其它 8个变量均差异显著 ( p<0 .0 5 ) ,该结果说明 5种次级洞巢鸟对巢位的选择具有其各自的需求。洞口横径、洞口纵径、洞处树直径、洞内径、巢距地高是巢位选择重要变量 ,它们决定不同种类对树洞的利用。巢损失多数出现在产卵之前和孵化阶段 ,44个繁殖失败的巢中有 35个在这两个阶段损失。大山雀的巢成功率最低 ,灰椋鸟的巢成功率最高。 5种鸟的孵化率都超过 90 %。人为破坏和动物捕食是繁殖失败的主要原因 ,占总数的 61 .4%。洞巢鸟巢位选择中的重要变量影响繁殖成功。普通跓繁殖是否成功受洞口横径和巢高影响 ,沼泽山雀受洞口纵径、树胸径和洞内径影响 ,大山雀受洞口横径、巢高和洞内径影响 ,灰椋鸟受洞内径和洞深影     

Influence of nest-site and individual quality on breeding performance in Merlins Falco columbarius

We examined the effects of nest-site quality and bird quality on breeding performance in male and female Merlins Falco columbarius from a long-term study in Saskatoon, Saskatchewan. In addition, we tested whether nest-site quality was associated with survival, as well as lifetime reproductive success (LRS). For females, nest-site quality had little influence on any of the measures of breeding performance or survival. Even so, when females switched nest-sites, they tended to move to better ones. Hatch date was repeatable for the same females occupying different nest-sites but not for the same sites occupied by different females. Among males, birds surviving past each age category tended to occupy nest-sites of higher quality, and LRS was positively correlated with nest-site quality. The relationship between nest-site quality and LRS was heavily influenced by the poorest nest-sites. When males switched nest-sites, they too tended to move to ones of higher quality. In addition, chick hatch date was repeatable neither for the same males occupying different sites nor for the same sites occupied by different males. As with most other raptors, male Merlins provide most of the food for the pair and their young during the breeding season, and differences in nest-site quality may have affected the effort needed by males to secure food. Female Merlins, however, appear still to have considerable control over the timing of breeding.     

Reproductive ecology of Tibetan Eared Pheasant Crossoptilon harmani in scrub environment, with special reference to the effect of food

We studied the nesting ecology of two groups of the endangered Tibetan Eared Pheasants Crossoptilon harmani in scrub environments near Lhasa, Tibet, during 1996 and 1999–2001. One group received artificial food from a nunnery prior to incubation whereas the other fed on natural food. This difference in the birds' nutritional history allowed us to assess the effects of food on reproduction. Laying occurred between mid-April and early June, with a peak at the end of April or early May. Eggs were laid around noon. Adult females produced one clutch per year. Clutch size averaged 7.4 eggs (4–11). Incubation lasted 24–25 days. We observed a higher nesting success (67.7%) than reported for other eared pheasants. Provisioning had no significant effect on the timing of clutch initiation or nesting success, and a weak effect on egg size and clutch size (explaining 8.2% and 9.1% of the observed variation, respectively). These results were attributed to the observation that the unprovisioned birds had not experienced local food shortage before laying, despite spending more time feeding and less time resting than the provisioned birds. Nest-site selection by the pheasants was non-random with respect to environmental variables. Rock-cavities with an entrance averaging 0.32 m² in size and not deeper than 1.5 m were greatly preferred as nest-sites. The birds were also more likely to place their nests in denser high-scrub and closer to streams. In the study area, the low availability of both cliff habitats and high-scrub patches suggested a limitation of sites suitable for nesting, which could be reflected in the between-year re-use of nest-sites (8.9%) and intraspecific nest parasitism (3.8%). Despite the apparent preference for certain nest-site variables, we found no effect of these on clutch fate, suggesting that the risk of nest predation was random.     

Selection of nest-site habitat by interior least terns in relation to sandbar construction

Federally endangered interior least terns (Sternula antillarum) nest on bare or sparsely vegetated sandbars on midcontinent river systems. Loss of nesting habitat has been implicated as a cause of population declines, and managing these habitats is a major initiative in population recovery. One such initiative involves construction of mid-channel sandbars on the Missouri River, where natural sandbar habitat has declined in quantity and quality since the late 1990s. We evaluated nest-site habitat selection by least terns on constructed and natural sandbars by comparing vegetation, substrate, and debris variables at nest sites (n = 798) and random points (n = 1,113) in bare or sparsely vegetated habitats. Our logistic regression models revealed that a broader suite of habitat features was important in nest-site selection on constructed than on natural sandbars. Odds ratios for habitat variables indicated that avoidance of habitat features was the dominant nest-site selection process on both sandbar types, with nesting terns being attracted to nest-site habitat features (gravel and debris) and avoiding vegetation only on constructed sandbars, and avoiding silt and leaf litter on both sandbar types. Despite the seemingly uniform nature of these habitats, our results suggest that a complex suite of habitat features influences nest-site choice by least terns. However, nest-site selection in this social, colonially nesting species may be influenced by other factors, including spatial arrangement of bare sand habitat, proximity to other least terns, and prior habitat occupancy by piping plovers (Charadrius melodus). We found that nest-site selection was sensitive to subtle variation in habitat features, suggesting that rigor in maintaining habitat condition will be necessary in managing sandbars for the benefit of least terns. Further, management strategies that reduce habitat features that are avoided by least terns may be the most beneficial to nesting least terns. © 2011 The Wildlife Society.     

Using super‐high resolution satellite imagery to census threatened albatrosses

This study is the first to utilize 30‐cm resolution imagery from the WorldView‐3 (WV‐3) satellite to count wildlife directly. We test the accuracy of the satellite method for directly counting individuals at a well‐studied colony of Wandering Albatross Diomedea exulans at South Georgia, and then apply it to the closely related Northern Royal Albatross Diomedea sanfordi, which is near‐endemic to the Chatham Islands and of unknown recent population status due to the remoteness and limited accessibility of the colonies. At South Georgia, satellite‐based counts were comparable to ground‐based counts of Wandering Albatross nests, with a slight over‐estimation due to the presence of non‐breeding birds. In the Chatham Islands, satellite‐based counts of Northern Royal Albatross in the 2015/2016 season were similar to ground‐based counts undertaken on the Forty‐Fours islands in 2009/2010, but much lower than ground‐based counts undertaken on The Sisters islands in 2009/2010, which is of major conservation concern for this endangered albatross species. We conclude that the ground‐breaking resolution of the newly available WV‐3 satellite will provide a step change in our ability to count albatrosses and other large birds directly from space without disturbance, at potentially lower cost and with minimal logistical effort.     

Effects of microhabitat preferences on kelp gull Larus dominicanus breeding performance

We examined microhabitat preferences and their adaptiveness for the kelp gull Larus dominicanus in one of its largest colonies in Patagonia. We quantified 13 habitat variables at 104 and 92 nest-sites and at 70 and 60 random points in 1998 and 1999, respectively. We recorded egg laying dates, hatching success, number of chicks fledged and breeding success at 92 of these nests in each of the study seasons. Compared to random points, nest sites had more vegetation cover and were closer to the nearest available bush, but they were located further from the nearest clearing for flight take-off, all variables included in the "vegetation" principal component. Nests were built on substrates with lower slopes and higher percentages of silt-clay, but with lower percentages of rock. In both years, hatching success, number of chicks fledged and breeding success were related positively to the vegetation principal component. Substrate slope and composition contributed to explain the variation in hatching and breeding success in 1998 and 1999, respectively. Our study shows that some kelp gull breeding parameters are affected by nest-site habitat characteristics. These associations were in most cases influenced by the timing of breeding, with earlier breeders being more successful. Vegetation effects and substrate characteristics were important variables in distinguishing random sites from nest sites, and in explaining variation in breeding performance, showing that their habitat preferences are adaptive and allowing us to detect both the pattern and process in kelp gull habitat selection.