Managing a breeding population of endangered Carnaby’s Black Cockatoo Calyptorhynchus latirostris on the edge of their range

Data include vegetation community surveys (transects and quadrats) at nine sites, nest site characterisations of 21 confirmed nesting hollows and measurements from eleven nestlings.

Nest site characteristics  
Nests were located following BirdLife Australia (2020) guidelines: observing hollow use by breeding and/or prospecting Carnaby’s pairs, identifying other signs of hollow use including chipping, feathers or feeding residue, using the ‘tap-and-flush’ method to determine if hollows were occupied and, finally, comprehensive searches of all potential hollows in suitable habitat using a lightweight camera (GoPro HERO7, San Mateo, California, USA) and click LED telescopic pen torch (Bunnings, Perth, Western Australia) attached to a 12m extendable fibreglass pole (Spiderbeam from TTS Systems, Stratford, Victoria) to look into hollows for the presence of breeding females (they don’t always flush), eggs or nestlings (Figure 2). Based on Carnaby’s requirements for nesting habitat (Saunders & Ingram 1987), nest searches were restricted to mature, hollow-bearing groves of open eucalypt woodland on or near the banks of the lower Murchison River. For each confirmed hollow (n = 21), we recorded GPS coordinates, tree species, tree diameter at breast height (DBH), tree and hollow entry height (m, using the Android app: Measure Height v1.4, Deskis OU), hollow entry type (chimney, spout, side, fork) and aspect (compass directions, vertical; BirdLife Australia, 2020). For a subset of hollows accessible by ladder (n = 12), we additionally recorded entry width (cm), hollow depth (cm) and width of the hollow floor (cm). Confirmed nesting trees were marked with numbered aluminium tags. Hollows showing no signs of use, or signs of use by other species, were noted but not measured or tagged. 

Nestling measurements
Nestlings (n = 11) were weighed (g, using a Pesola 1000g spring balance scale, Schindellegi, Switzerland) and folded left wing measured (mm, using a stopped rule). Nestlings were aged by comparing the folded left wing measurement with a growth curve of the folded left wing measurements of nestlings of known age (Saunders & Ingram 1998, Saunders et al. 2020b). Nestling condition was assessed by comparing the measured nestling mass for a measured folded left wing length at MHS (n = 11, limited to nestlings with folded left wing length > 50mm) with the benchmark body mass for that wing length (Saunders et al. 2020b). Lay dates were estimated based on nestling age and an incubation period of 29 days (Saunders 1982) for 30 breeding attempts. The egg-laying period was determined based on estimated lay dates of the first and last clutches in each season.
Vegetation surveys
To assess the condition and quality of foraging and nesting resources available to the breeding population at MHS, we established eight permanent vegetation monitoring points, four in banskia woodland (S2-S5) and four in riverine eucalyptus woodland (S6-S9; Figure 3). At each point, we marked a permanent vegetation quadrat (20m x 20m) and 50m transect. We oriented the quadrats on the compass (corners at NEWS) and laid out transects in a northerly direction starting from the midpoint of the southern edge of each quadrat. Vegetation surveys followed Department of Biodiversity, Conservation and Attractions (DBCA) Standard Operating Procedures (SOPs) 6.1 (Clarke 2009a) and 6.2 ( Clarke 2009b). Vegetation surveys were conducted in September 2021, when both annual and perennial species were present and many species were in flower, aiding identification. 
We recorded all plant species present within each quadrat. Herbarium specimens were collected and collated into a field herbarium book for identification on-site or in the herbarium. Vegetation structure, vegetation condition (healthy, not healthy, dead), soil type and landform within each quadrat were also noted. We used the point-intercept method (Jonasson 1983, 1998, De Stefano et al. 2021) along each transect, recording vegetation at 1m intervals. Variables measured at each point were ground cover (vegetation, rock, leaf litter, dead wood, bare ground), burn status and, if vegetation was detected, species, condition, canopy height (m, using a 5m tape measure or, if plants taller than 3m, the Android app: Measure Height v1.4, Deskis OU) and phenology (presence of flowers, fruit or new leaf growth). All observations were recorded in the field using CyberTracker software on a Samsung smartphone.

本数据集包含九处地点的植被群落调查（样带和样方）、21个已确认巢穴的特征描述以及11只雏鸟的测量数据。

巢穴特征
巢穴的定位遵循了澳大利亚鸟类生活（2020）的指南：观察繁殖和/或觅偶的Carnaby鸟对使用洞穴的情况，识别其他洞穴使用迹象，包括啄木、羽毛或喂食残留物，使用‘轻敲冲洗’法以确定洞穴是否被占用，并最终，使用轻便摄像机（GoPro HERO7，加州圣马特奥，美国）和点击LED望远镜手电筒（Bunnings，珀斯，西澳大利亚）连接至12米可伸缩玻璃纤维杆（TTS Systems，维多利亚州斯特拉特福德生产的Spiderbeam）全面搜索适宜栖息地中所有潜在的洞穴，以查看是否存在繁殖雌鸟（它们并不总是会被冲走）、蛋或雏鸟（图2）。基于Carnaby对巢穴栖息地的要求（Saunders & Ingram 1987），巢穴搜索被限制在成熟、具有洞穴的开放式按树林中，这些树林位于或靠近下游Murchison河的河岸。对于每个已确认的洞穴（n = 21），我们记录了GPS坐标、树种、胸高直径（DBH）、树木和洞穴入口高度（m，使用Android应用程序：Measure Height v1.4，Deskis OU）、洞穴入口类型（烟囱、喷口、侧面、分叉）和朝向（指南针方向，垂直；BirdLife Australia，2020）。对于部分可通过梯子进入的洞穴（n = 12），我们额外记录了入口宽度（cm）、洞穴深度（cm）和洞穴底部宽度（cm）。未显示出使用迹象或显示其他物种使用迹象的洞穴被记录，但未进行测量或标记。

雏鸟测量
对11只雏鸟进行了称重（g，使用瑞士Schindellegi的Pesola 1000g弹簧秤）和折叠左翼的测量（mm，使用停止尺）。通过将折叠左翼的测量值与已知年龄的雏鸟折叠左翼测量值生长曲线进行比较（Saunders & Ingram 1998，Saunders et al. 2020b），对雏鸟进行了年龄鉴定。通过将MHS测量的折叠左翼长度处的雏鸟质量与该翼长度的基准体重进行比较（Saunders et al. 2020b），评估了雏鸟的状况。基于雏鸟年龄和29天的孵化期（Saunders 1982）估计了30次繁殖尝试的产蛋日期。根据每季节中第一窝和最后一窝的估计产蛋日期确定了蛋的产蛋期。

植被调查
为评估MHS繁殖种群可用的觅食和巢穴资源的状况和质量，我们建立了八个永久植被监测点，其中四个位于Banskia树林（S2-S5）和四个位于河岸按树林（S6-S9；图3）。在每个监测点，我们标记了一个永久植被样方（20m x 20m）和50m样带。样方以指南针为基准（角点在NEWS），样带从每个样方南部边缘中点开始向北方展开。植被调查遵循了生物多样性、保护与吸引力部（DBCA）标准操作程序（SOPs）6.1（Clarke 2009a）和6.2（ Clarke 2009b）。植被调查于2021年9月进行，当时既有年度植物又有多年生植物，许多植物都在开花，有助于识别。我们记录了每个样方中存在的所有植物物种。采集了植物标本，并将其整理成野外植物标本簿，以便在现场或标本馆进行鉴定。在每个样方中，我们还记录了植被结构、植被状况（健康、不健康、死亡）、土壤类型和地形。我们使用点截法（Jonasson 1983，1998，De Stefano et al. 2021）沿样带进行，记录每1米间隔的植被。在每个监测点测量的变量包括地面覆盖（植被、岩石、落叶、枯木、裸地）、燃烧状况，以及如果检测到植被，则记录物种、状况、树冠高度（m，使用5米卷尺或如果植物高于3米，则使用Android应用程序：Measure Height v1.4，Deskis OU）和物候（花朵、果实或新叶生长的存在）。所有观察结果均使用Samsung智能手机上的CyberTracker软件在现场记录。