Brahminy Kite breeding Port Stephens The Whistler 13 (2019): 1-9 Brahminy Kite: two consecutive breeding seasons at Port Stephens, NSW, compared Lois Wooding 14/4 Muller Street, Salamander Bay, NSW 2317, Australia [email protected] Received 3 June 2018; accepted 17 January 2019; published on-line 10 March 2019. The nesting behaviour of a pair of Brahminy Kite Haliastur indus at Lemon Tree Passage, NSW, was compared over two consecutive breeding seasons (2016 and 2017), following close observation of the entire cycle from nest-building to juvenile independence in 2017. Incubation took 34-36 days, and the nestling period 50 days. New or supplementary nest building, courtship, parental and juvenile behaviours are described, and a fledged juvenile was followed for 38 days. An attempt was made to study the adult birds when they were away from the nest, and to define their general territory and hunting range throughout the breeding cycle. INTRODUCTION AND BACKGROUND Additional time spent tracking the fledged juvenile once it left the nest site was not recorded. The area was visited A pair of Brahminy Kite Haliastur indus has been regularly. The duration of observation periods varied, as recorded at Lemon Tree Passage, at the expanding did the time of day when they were conducted. Most nest observations were made from a vehicle parked southern limit of the species’ breeding distribution in approximately 50 m from the base of the nest tree at a NSW, since 2010 (Stuart 2011-2016; Wooding viewing angle of approximately 75˚ to the nest. Off-nest 2017). Local residents were aware of nesting observations were made from six different locations, five activity during that time, but confirmation of an of which enabled localised scanning of shorelines, creeks, active nest was not reported until May 2016 islands and bays. The elevation of the sixth site provided (Wooding 2017). A new nest, constructed in 2017, an overall view of the estuary in the region of Lemon Tree presented an opportunity to observe nest Passage. Field notes were transcribed and, where construction; compare nest sites and nesting applicable, logged on an Excel spreadsheet, but a detailed behaviour; follow a fledged juvenile, and to try and log of parental time budgets was not kept. document the routine of the adult birds when not at It should be noted that distance, weather, and restricted the nest. Meanwhile, a population study in northern nest views presented constant challenges, which may have Australia that covered the egg-laying season, nest influenced the description of individual actions or the sex sites, breeding density and success and diet (Riddell assigned to the adult birds. 2017) complements the behavioural aspects reported by Rourke & Debus (2016) and Wooding (2017). Here I present supplementary information on RESULTS breeding behaviour and the post-fledging period for the pair breeding at Lemon Tree Passage. The 2016 nest site The 2016 nest site was checked regularly between MATERIALS AND METHODS December 2016 and May 2017. No obvious signs of deterioration or damage were noted despite the The same equipment and methodology was used as in the passage of storms and high winds (Figure 1). More previous study (Wooding 2017). Observations were made frequent nest-site checks began in mid-May 2017. with binoculars (Swarovski EL 10x50 SV) and a spotting scope (Swarovski HD 20x60). Photos and videos were One or both adult birds were found at the nest site taken using a Nikon P900 camera, and a Canon EOS 7D several times between 31 May and 6 June, but they Mark 11 camera equipped with a Canon EF 100-400 f/4.5- did not appear to interact, and the nest was not 5.6 IS USM lens and a 1.4 extender. Distance attended. measurements were taken from Google Earth 2017. On 31 May both adults were found in the 2016 nest- The 2017 study involved a total of 118 observation hours: tree, each perched approximately 3 m from the nest 66 h at the nest, and 52 h studying off-nest behaviour. but on opposite sides of it, with their backs to each 1 Brahminy Kite breeding Port Stephens The Whistler 13 (2019): 1-9 other and to the nest. They maintained this position for 90 min before the male flew to the estuary. Observation continued for a further 20 min, but the female did not move. On 1 June the female was seen in the same position. The male flew in 38 min later, and perched on the same branch as before. After 4 min, the male circled overhead seven times and flew away. The male returned 12 min later, sat for 8 min, circled again, then flew to the estuary. There was no detectable response from the motionless female. Between 2 June and 6 June a Brahminy Kite was seen circling over the nest site several times, and on 6 June the female was again observed perching Figure 1. The 2016 Brahminy Kite nest, Lemon Tree motionless on the same branch for two hours. No Passage. Photo: Lois Wooding Brahminy Kites were seen at the site after 6 June. The first observation of a Brahminy Kite carrying a stick occurred on 28 May 2017, and although regular stick-carrying continued, no nest renovations were detected. A new nest was suspected and eventually found on 26 June. The disused nest was checked monthly throughout the breeding season; it remained sound, unchanged and unoccupied. The 2017 nest On 26 June, an incomplete, well-hidden nest (Figure 2) was located in a mature Blackbutt Eucalyptus pilularis (identified from Cronin 2002), situated on an urban lot approximately 0.28 km south of the Figure 2. The 2017 Brahminy Kite nest, Lemon Tree 2016 nest-site and 0.4 km from the estuary. The tree Passage. Photo: Lois Wooding had been severely lopped. The main trunk terminated at a height of approximately 20 m, and Nest-building material was mainly sourced from the upper canopy was formed by two large lateral Bulls Island Nature Reserve, a strip of land covered branches growing at acute angles to the trunk. The in Grey Mangroves Avicennia marina and Swamp branch on which the nest was constructed leaned Sheoak Casuarina glauca (identified from Cronin over into a strip of urban forest. The treed area, 2002), which forms the east side of the narrow strait which bordered a small park, was surrounded by a known as Lemon Tree Passage. Stick-carrying was tall chain-link fence. A row of fully-developed mostly observed from Site 1 (Figure 3). The adult urban lots backed onto the site’s west side (Figure 3- male carried sticks in the bill, not the talons, and was insert). The combination of fence, houses and frequently mobbed by 40-50 Little Corellas Cacatua neighbouring trees prevented access to the base of sanguinea, but no sticks were dropped. the nest-tree, and restricted views of the nest. In this urban area human activity was moderate, and the By counting the number of sticks visible on enlarged kites seemed unaffected by traffic noise. photographs it was estimated that 250 sticks, 20% of which were ≥3 cm in diameter, and >1 m in length, Nest preparation and courtship were required to fill the triangular fork and establish the nest platform. Over 41 days, this number would Between 28 May and 8 July (41 days) stick-carrying require gathering and transporting approximately six was observed daily, more frequently in the morning, sticks per day. The shortest distance between Bulls until nest completion. On at least three occasions Island and the nest was 0.83 km, which would both adults were observed carrying sticks at the same require the male to fly 5-6 km/day carrying a stick, time. The female was rarely seen flying after mid- for a total distance of between 205 and 246 km over June, but the male continued to carry sticks. the entire nest-building period. 2 Brahminy Kite breeding Port Stephens The Whistler 13 (2019): 1-9 Figure 3. The Lemon Tree Passage region, Port Stephens Estuary, showing nest locations, estuary viewing points, and the suggested territory of a pair of Brahminy Kites during the 2017 breeding cycle. When the nest was discovered on 26 June, it became observed bringing fish to the female on 26 June, 3 obvious that the female was the principal nest- July and 6 July. The fish was always eaten while builder, taking considerable time to work the perched on a branch near the nest. Copulation was branches, delivered by the male, into the space witnessed on 6 and 8 July. created by a trisecting, vertical fork along the east- leaning, lateral limb of the nest tree. Nest height was After depositing a stick at the nest, the male estimated at 25 m. Once the interwoven branches frequently circled 10-30 m above the nest site, an formed a platform that comfortably accommodated exhibition of slip-sliding, aerodynamic control the movement of both adults, the female interlaced gracefully performed with barely a wing-flap. more branches around the edge of the structure to Circling was often followed by a rapid, spiralling rim the nest. On 8 July the male made several trips ascent to a height where, reduced to a distant speck, to the nest carrying long strands of grass, which the the male flew away. Territorial display was female arranged in the nest cup. The nest was assumed. The female was also seen circling when thought to be complete. leaving the nest, but the action was less frequent, less dramatic, and more purposeful, a manoeuvre Though not visible in its entirety, nest length was seemingly more related to gaining the height needed estimated at >1 m, and given that the upper thighs of to fly over the town-site to the estuary.