Australian Field Ornithology 2020, 37, 26–38 http://dx.doi.org/10.20938/afo37026038

The avian diet of the Australian Falco longipennis breeding in an urban parkland in southern Victoria

Craig G. Morley

P.O. Box 1047, Geelong VIC 3220, Australia Email: [email protected]

Abstract. A total of 129 hours of observation was completed on a pair of Australian Hobbies Falco longipennis through two complete breeding seasons, from early courtship until at least a month after fledging. The pair raised three fledglings in the 1992–1993 breeding season and two fledglings in 1993–1994. Avian prey, prey transfer, prey partitioning, prey-delivery rates, potential impact on the local community and hunting behaviour are described. The avian diet was mainly small passerines and a few small parrots. The majority of prey by species was House Sparrows Passer domesticus and Common Starlings Sturnus vulgaris. At least 55% by number and 64% by biomass were introduced species. The mean mass of identified avian prey was 36 g. Bird species with mass of ≤25 g made up 71% by number and 49% by mass of the diet. In each breeding season, the prey-delivery rate was lowest during incubation (0.17 item/h in 1992–1993 and 0.14 item/h in 1993–1994, and 3.7 and 2.8 g/h, respectively) and increased during the nestling stages (0.65 and 1.12 items/h; 25.7 and 35.2 g/h, respectively). In 1992–1993, it continued to increase in the fledgling period (1.00 item/h and 32.5 g/h) but in 1993–1994 it decreased in the fledgling period (0.50 item/h and 15.4 g/h) after brood-reduction in the nest. Through each complete season, the prey-delivery rates were 0.57 item/h and 19.1 g/h (three fledglings 1992–1993) and 0.45 item/h and 12.7 g/h (two fledglings 1993–1994). Two species—Crested Shrike-tit Falcunculus frontatus and Common Greenfinch Chloris chloris—have not previously been recorded as prey of the .

Introduction were involved. Prey partitioning and prey-delivery rates are also described and quantified, along with supplementary observations of hunting behaviour on and insects. The breeding biology of the Australian Hobby Falco Australian Hobbies have bred in the Geelong parkland in longipennis has been described in some detail in several most years since at least 1991 (CGM pers. obs.), including previous studies (Cupper & Cupper 1981; Hollands a successful breeding event in 2004–2005. 1984; Czechura & Debus 1986; Metcalf 1989; Debus et al. 1991; Rosalky 2005) and has been summarised in several reviews (Marchant & Higgins 1993; Olsen Study area and methods et al. 1993; Olsen 1995; Ferguson-Lees & Christie 2001; Debus 2019). Czechura & Debus (1986) and Marchant The nests used by the Australian Hobbies in each breeding & Higgins (1993) listed prey species for the Australian season (1992–1993 and 1993–1994) were in Eastern Park, Hobby. Dietary studies or prey lists have been presented Geelong (38°09'S, 144°23'E; 50 m above sea level), an for southern Victoria (Melbourne: Norris 2006), New South area of 80 ha, ~1.5 km east of the Central Business District Wales (Northern Tablelands: Debus et al. 1991; Southern of Geelong. Within the City of Geelong, this park is the Tablelands: Price-Jones 1983; Olsen et al. 2006, 2008), only significant area of parkland that provides extensive Western Australia generally (Johnstone & Storr 1998), bird habitat. It consists predominantly of open areas and the southern Northern Territory (Aumann 2001) and the playing fields bordered by large trees—Sugar Gums northern Australian tropics (Aumann et al. 2016). Eucalyptus cladocalyx, Monterey Pines Pinus radiata, In common with other members of the , the Stone Pines P. pinea and Monterey Cypresses Cupressus Hobby shows sexual dimorphism, with the male (210 g) macrocarpa—with little if any understorey. The Geelong being smaller and lighter than the female (290 g) (Marchant Botanic Gardens, an area of 4 ha within the parkland, is far & Higgins 1993; Olsen 1995). During the earlier stages of more densely planted than the rest of the parkland, with a breeding, until the nestlings no longer require brooding, much wider variety of vegetation structure and type, with the male is responsible for all avian prey, returning with flowering and fruiting exotic and native trees, shrubs, and it to the nest area. The male captures prey over a wide perennial and annual forbs and grasses. size range until the female begins hunting, after which, on The Hobbies used two different disused nests of Little average, he captures smaller prey than previously, and Ravens Corvus mellori in Monterey Pines in the north- smaller prey than does the female (Debus et al. 1991; eastern section of the parkland during the two breeding Marchant & Higgins 1993). seasons. This species is known to favour particular This paper describes and quantifies the avian diet perches, as the study pair did, near nest-trees for guard of a pair of breeding Hobbies in an urban parkland in posts, copulation, plucking prey, transferring prey and feeding fledglings (Marchant & Higgins 1993; CGM pers. Geelong, in central southern Victoria, during the late obs.). winter to summer of 1992–1993 and 1993–1994. From the similarities in plumage and behaviour over these two Observations over the two breeding seasons were made breeding seasons, it is likely that the same individual birds from the ground, at a distance of ~40 m from the nest-tree, Avian diet of breeding Australian Hobbies, Geelong, Victoria 27

with the aid of binoculars (8 x 24, 7 x 50) and a telescope were removed from the site. Remains in pellets were not (5-cm objective lens) for a total of 129 hours on 140 days included in the prey count if they could be accounted (Table 1). Some additional photographs were taken in for by observations of prey delivered in the previous 2004–2005. The nestling period was taken to start following c. 3 days, because an item may be shared among the a change in the behaviour of the adults. During incubation, Hobby family with the remains appearing in several pellets. when the male delivered prey, the female left the nest This approach is consistent with the principle of ‘minimum to feed while the male settled on the nest. Egg(s) were number of (prey) individuals’ (MNI) as used in comparable considered to have hatched when the female no longer left dietary studies (e.g. Olsen et al. 2008; Olsen 2014). the nest to consume prey, while the male briefly visited the Prey-delivery rates were calculated as the number of nest to deliver prey and returned to a nearby perch. The prey items delivered (or mass of prey delivered) per unit fledgling period was taken to start when the first nestling observation time (in minutes) in each stage of the breeding flew from the nest-tree, preceded by ‘branching’ when cycle. These figures were converted to an hourly rate (i.e. nestlings left the nest for perches in the nest-tree. After × 60), because observations were mostly spread through 8 January in 1993 and after 4 January in 1994, structured the day (Table 1), although some early-morning deliveries observations ceased; no Hobbies were observed in the might have been missed and morning deliveries were vicinity of the nest area during casual observations. In under-represented for incubation in 1992 and the brooding most phases of both seasons, the observation schedule phase in 1993. All times are Eastern Australian Standard covered morning to evening, except during incubation in Time. 1992–1993 and brooding in 1993–1994, when it covered only from the middle of the day until the evening. Abundance estimates (Appendix 1) for prey and other avian species in the parkland were derived from data Avian prey items were identified by sight from plumage collected from three 2-ha survey sites in the park, in and size characteristics where possible, by feathers accordance with the method used for the 20-minute retrieved from plucked prey, and from prey remains and search method (Loyn 1986) and the Australian Bird Count regurgitated pellets collected from beneath feeding/ (Ambrose 1989). Each 2-ha site was surveyed three times plucking perches. Coarse identification was made by in each breeding season, during late winter (courtship), size. Some pellets, remains and feathers were identified spring (late nestling) and summer (late fledgling stage). by Museum Victoria staff. The mass of prey species was The abundance figure for each bird species is the number estimated from data in Czechura & Debus (1986) and of birds per hectare per survey. One of the three survey Rogers et al. (1986, 1990). sites was adjacent to the Hobbies’ nest area. Care was taken not to double-count prey items observed The vulnerability index for a bird species was calculated being brought to the nest-site and then found several from the percentage occurrence in the Hobby prey divided days later as pellets or remains. All pellets and prey items by the percentage abundance of the species in the bird

Table 1. Calendar of events and schedule of observations (number of visits, number of days and times) at an Australian Hobby nest-site, Geelong, Victoria, through two complete breeding seasons. Days are shown as day/month/year.

Stage Dates No. visits No. days Total time (h) Time of day

1992–1993 Courtship 16/8–25/9 28 19 15.0 0830–1900 Incubation 4–30/10 32 19 11.5 1250–1950

Nestling Female brooding 31/10–12/11 14 10 8.3 0920–1855 Female off nest 15/11–5/12 24 17 17.9 0830–1940 Fledgling 5/12/92–8/1/93 14 12 14.0 0850–1940 Season total 112 77 66.7

1993–1994 Courtship 22/8–27/9 35 22 22.1 0820–1900 Incubation 28/9–29/10 20 14 14.1 0825–1930 Nestling Female brooding 2–15/11 6 6 5.1 1150–1810 Female off nest 17/11–7/12 9 8 4.7 0730–1830 Fledgling 8/12/93–4/1/94 26 13 16.0 0800–1930 Season total 96 63 62.0

Total both seasons 208 140 128.7 0730–1950 28 Australian Field Ornithology C.G. Morley

population in the study area. An index of 1 indicates that Individuals of four prey species—Crested Shrike-tit the species is taken in exact proportion to its abundance in Falcunculus frontatus, Willie Wagtail Rhipidura leucophrys, the study area. An index >1 indicates that the prey species House Sparrow and —were obviously is taken more frequently than expected and <1 that it is juvenile, based on feather development and coloration, taken less frequently than expected (see Newton 1986). and in the case of the Shrike-tit the flaky surface on the Percentage abundance of each prey species in the study upper mandible and the buff tips to black feathers of the area was the total number of individuals for a particular forehead. species multiplied by 100, then divided by the total number Through the two complete breeding seasons in the of birds for all species observed in the nine surveys during Geelong urban parkland, the Hobbies took mainly each breeding season. introduced bird species. House Sparrows (28% by number) and Common Starlings (16%) together made up Results 44% of the avian diet by number and 58% by biomass. The Starlings tended to be juveniles, caught later in the Diet season. Other introduced species captured by the Hobbies were Common Greenfinch (3% by number), European The diet of the breeding Australian Hobbies consisted of Goldfinch Carduelis carduelis (2%) and Eurasian Skylark small birds supplemented with flying insects. A total of (5%). When combined, introduced species made up 55% 13 bird species was recorded as prey: seven in 1992–1993 of the avian diet by number and 64% by biomass. If the and 11 in 1993–1994 (Table 2). Five of these species— category of ‘sparrow-sized’ prey (23% by number) is all Budgerigar Melopsittacus undulatus, House Sparrow considered to be Sparrows and that of ‘starling-sized’ prey Passer domesticus, Common Greenfinch Chloris chloris, (1%) to be Starlings, then the avian diet of the Hobbies was Eurasian Skylark Alauda arvensis and Common Starling 79% introduced species by number and 84% by biomass Sturnus vulgaris—were recorded as prey in both seasons. over the two seasons.

Table 2. Avian prey of a pair of breeding Australian Hobbies in Geelong urban parkland for the breeding seasons 1992–1993 and 1993–1994: number of prey items, from direct observation of the Hobbies returning to the nest- site, and from prey remains found in situ and in regurgitated pellets. Mass of prey is based on data in Czechura & Debus (1986) and Rogers et al. (1986, 1990). *Mass of unknown is the mean mass of all identified avian prey items, + = introduced species.

Prey species Mass (g) 1992–1993 1993–1994 Total

Identified birds

Purple-crowned Lorikeet Glossopsitta porphyrocephala 45 1 1

Budgerigar Melopsittacus undulatus 30 3 3 6

White-plumed Honeyeater Ptilotula penicillata 20 1 1

Striated Pardalote Pardalotus striatus 12 2 2

Crested Shrike-tit Falcunculus frontatus 30 1 1

Willie Wagtail Rhipidura leucophrys 20 1 1

+House Sparrow Passer domesticus 25 13 14 27

+Common Greenfinch Chloris chloris 23 2 1 3

+European Goldfinch Carduelis carduelis 15 2 2

+Eurasian Skylark Alauda arvensis 20 1 4 5

Welcome Hirundo neoxena 15 1 1

Silvereye Zosterops lateralis 12 1 1

+Common Starling Sturnus vulgaris 75 8 7 15

Unidentified birds Pardalote-sized ~12 2 2

Sparrow-sized ~25 15 7 22

Starling-sized ~75 1 1

Unknown 36* 4 4

Total 46 49 95 Avian diet of breeding Australian Hobbies, Geelong, Victoria 29

In each of the two breeding seasons, the Sparrow to take it, then returned to the nest. Later in each fledgling (including ‘sparrow-sized prey’) by number (61% in period, some prey transfers were aerial. For instance, 1992–1993 and 43% in 1993–1994) and biomass on Day 13 of the 1992–1993 fledgling period, the female (44% and 34%, respectively) and Starling (including returned with a blue Budgerigar. The young Hobby flew off ‘starling-sized prey’) by number (20% and 14%) and calling to meet the female, which hung in the air, holding biomass (43% and 34%) made up the majority of avian the prey in her foot, while the fledgling took it in its beak prey. and then transferred the prey to its feet. On Day 17 of the 1992–1993 fledgling period, the male returned with a female Over the two breeding seasons, native species (not Sparrow that was dropped in mid air to a fledgling. On including Budgerigars or ‘pardalote-sized’ prey) made up Day 22 of the 1992–1993 fledgling period, the female 8% (by number) and 5% (by biomass) of all avian prey. returned with prey and rose on flat wings, allowing the Budgerigars contributed 6% by both number and biomass. fledglings to fly to her, the female fledgling beating her two The most numerous prey species, the Sparrow, has a male siblings to the prey. On Day 17 of the 1993–1994 mass of 25 g. Identified avian prey items with a mass of fledgling period, an adult returned and transferred prey ≤25 g made up 45% by number and 31% by mass of the to a fledgling in a foot-to-foot pass. As the fledglings Hobbies’ total avian prey. Including ‘sparrow-sized’ and developed, it became more difficult to confirm the method ‘pardalote-sized’ prey, these figures were 71% by number of prey transfer, as the fledglings were more active and and 49% by mass. The mean mass of identified avian mobile, flying away from the observer to harass the adults prey was 36 g (Table 2). No prey items were heavier than returning with prey. 75 g. A wing of a Red Wattlebird Anthochaera carunculata (probably a juvenile, with feathers not fully grown and with All prey passed to the female was already dead, except buff markings) found on the ground might have been prey for a Budgerigar that was still alive when passed to her remains, as it was in the area where the Hobby fledglings during the 1992–1993 courtship period. After she had were active and being fed, but there was sufficient doubt taken it from the male, she killed it with a nip behind the that this item was not included in the analysis. neck and proceeded to pluck and consume it. In each breeding season, the fledgling Hobbies At no time were the adults observed consuming feathered vigorously chased Galahs Eolophus roseicapilla and Rock prey without first plucking it (Figure 1). Only the fledglings, Doves Columba livia but there was no evidence that either early in their development, when given avian prey of these species was taken as prey. On one occasion, a c. 5–6 days after fledging, attempted with little success to pure-white briefly lay exhausted on the ground swallow feathered pieces of prey. after repeated tail-chases by one and sometimes two of Figures 2–3 supplement these observations with the juvenile Hobbies, presumably for practice (‘play’), but evidence for the use of prey in an attempt to entice it was not captured and at no time were the Hobbies seen branching nestlings to fledge. striking the Dove. Both the Galah and the Dove are much heavier than the prey taken by the adult Hobbies in this study and are not considered as potential Hobby prey. Prey partitioning The pair of Hobbies and young also fed on flying insects. There was partitioning of prey based on size between the Some pellets contained elytra from beetles, probably male and female Australian Hobbies in each of the two cockchafers (Scarabaeidae), consistent with scarabs breeding seasons. In 1992–1993, during the stages when featuring in some other studies (e.g. Olsen et al. 2006, only the male was hunting (courtship, incubation and early 2008). During the incubation period in 1992, the female nestling period), prey seen to be delivered by him averaged Hobby was observed catching flying insects in the nest 29.2 g (n = 17), 14% of the male mass (Table 3). If prey area, while the male was on the nest. On Day 5 of the remains (n = 3) from early in the breeding cycle (when fledgling period in 1992–1993, a fledgling attempted only the male was hunting) are included, the average is to capture flying insects (although it was not clear if the 29.5 g, also 14% of adult male mass. During the late nestling attempt was successful); on Day 35, two fledglings were and post-fledging stages, after the female started hunting observed catching flying insects and returning to high (c. Day 27 of the nestling period), prey seen delivered by perches to consume them. The Hobbies, particularly the the male averaged 24.8 g (n = 10), 12% of adult male mass; adults, were observed catching and feeding on prey delivered by the female during this period averaged (Anisoptera) in flight. Early in the 1993 incubation period, 67.5 g (n = 6), 23% of adult female mass. the male hawked for dragonflies. In 1993–1994, during the stages when only the male Prey transfer was hunting (courtship, incubation and nestling stages), the mass of identified prey delivered averaged 25.4 g (n = 17), 12% of adult male mass (Table 4). If prey remains Prey items brought to the nest area by the male Hobby (n = 9) from early in the breeding season are included, were occasionally consumed (partly or wholly) by him the average is 32.2 g, 15% of adult male mass. From the but usually prey items were transferred to the female at day of fledging (the day that the female started hunting), a perch. She consumed them (partly or wholly) or took prey delivered by the male averaged 21.7 g (n = 3), 10% them to the nestlings or fledglings. On occasions late in of average adult male mass; prey delivered by the female the post-fledging period, the male passed prey directly averaged 40.3 g (n = 4), 14% of average adult female to the fledglings. Only once, early in each nestling stage, mass. the male returned with prey and briefly visited the nest to deliver the prey to the female. On every other occasion Over the two breeding seasons, identified prey delivered when he returned with prey, the female came from the nest by the male (ranging in size from Striated Pardalote 30 Australian Field Ornithology C.G. Morley

Pardalotus striatus to Starling) varied from 6 to 36% of the male Hobby’s mass and identified prey delivered by the female (Sparrow to Starling) was from 9 to 26% of the female Hobby’s mass (Figure 1).

Prey-delivery rates

Observations were made between 0730 h and 1950 h. The earliest observed prey delivery was at 0910 h and the latest at 1915 h. The latest morning delivery was at 1152 h and the earliest afternoon delivery at 1211 h. The observation schedule largely accounted for variation in delivery rate by time of day. Deliveries were made at varying times during the days when observations were made, and there did not seem to be a particular period of time during the day when deliveries ceased. In 1992–1993, the mean prey-delivery rate was Figure 1. Adult female Australian Hobby perched with 0.57 delivery/h (one delivery every 105 minutes of plucked prey (Common Starling), apparently making an unsuccessful attempt to entice the juvenile in Figure 2 observation), and in 1993–1994 only 0.45 delivery/h (one to fly. After several minutes, she flew from this perch and delivery every 133 minutes). In 1992–1993, three young dropped the carcass onto the nest (see Figure 3). Eastern Hobbies successfully fledged but in 1993–1994 only two Park, Geelong, December 2004. Photo: Craig G. Morley fledged, although initially there were at least three, possibly four, nestlings in the latter case. The male’s prey-delivery rate varied through both the 1992–1993 and 1993–1994 breeding seasons (Table 5). During incubation in each season, it was lowest (0.17 and 0.14 item/h, respectively). During courtship, it was similar in the two breeding seasons (0.33 and 0.32 item/h) and, in both seasons, after the low rate during incubation, there was an increase during the nestling stage. The male’s provisioning rate rose in each season while the female was brooding, but this increase was much greater in 1993–1994 (from 0.17 to 0.48 item/h in 1992–1993 cf. from 0.14 to 0.98 item/h in 1993–1994). In each breeding season, the male’s delivery rate showed a further increase when the female ceased brooding. At this stage, the female was off the nest and the young were feathered and able to thermoregulate. In 1992–1993, the female provided food for the young at Figure 2. Juvenile Australian Hobby ‘branching’ at the top an earlier stage than in 1993–1994. In 1993–1994, when of the nest-tree, Eastern Park, Geelong, December 2004. the female was not brooding (from c. Day 15 of the nestling Photo: Craig G. Morley stage), the provisioning rate of the male only (1.28 items/h) was greater than that of the male and female combined during the same period in 1992–1993 (0.73 item/h). During the fledgling period in 1992–1993, the parental provisioning rate (1.00 delivery/h) continued to increase with three fledglings to feed. In 1993–1994, the provisioning rate late in the nestling stage was 1.27 deliveries/h. For the entire nestling period in 1993–1994, the rate was 1.12 deliveries/h but that declined to 0.50 delivery/h with two fledglings to feed. During courtship, the prey-delivery rate averaged 6.9 (1992–1993) and 7.0 g/h (1993–1994) (Table 5). During incubation, it was 3.7 (1992–1993) cf. 2.8 g/h (1993–1994); during the early nestling period while the female was brooding, it was 18.1 cf. 38.6 g/h, respectively; and when the female was off the nest later in the nestling period, it was 29.2 (male and female hunting in the 1992–1993 Figure 3. Adult female Australian Hobby flying to nest to season) cf. 31.5 g/h (only male hunting in 1993–1994). dump prey after unsuccessful attempt to have juveniles Over the two complete nestling stages, the rates were fly from the nest-tree, Eastern Park, Geelong, December 25.7 cf. 35.2 g/h, and in the two fledgling periods 2004. Photo: Craig G. Morley 32.5 cf. 15.4 g/h, respectively. Avian diet of breeding Australian Hobbies, Geelong, Victoria 31

Table 3. Avian prey of a pair of breeding Australian Hobbies in Geelong urban parkland from August 1992 to January 1993: number of prey items recorded by direct observation of the adults returning to the nest area. + = introduced species; M = male, F = female, ? = sex unknown; stages of breeding cycle: c = courtship, i = incubation, en = early nestling (female brooding), ln = late nestling (female off nest), fl = fledgling.

Prey species M c M i M en M ln F ln M fl F fl ? fl Total

Identified birds Budgerigar 1 1 2

Striated Pardalote 2 2

+House Sparrow 1 2 1 3 1 1 9

+Common Greenfinch 1 1 2

+Eurasian Skylark 1 1

+Common Starling 1 1 2 1 1 6

Unidentified birds

Sparrow-sized 1 1 7 2 4 15

Starling-sized 1 1

Total 5 2 4 10 3 6 3 5 38

Table 4. Avian prey of a pair of breeding Australian Hobbies in Geelong urban parkland from August 1993 to January 1994: number of prey items recorded by direct observation of the adults returning to the nest area. + = introduced species; M = male, F = female, ? = sex unknown; stages of breeding cycle: c = courtship, i = incubation, en = early nestling (female brooding), ln = late nestling (female off nest), fl = fledgling.

Species M c M i M en M ln M fl F fl ? fl Total

Identified birds Budgerigar 1 1

Willie Wagtail 1 1

+House Sparrow 2 1 2 5

+Common Greenfinch 1 1

+Eurasian Skylark 2 2 4

Welcome Swallow 1 1

+Common Starling 1 1 2

Unidentified birds

Pardalote-sized 1 1 2

Sparrow-sized 2 3 2 7

Unknown 2 1 1 4

Total 7 2 5 6 3 4 1 28

The prey-delivery rates by biomass for the two complete several assumptions were made. The Hobbies were breeding seasons were 19.1 g/h (three fledglings, considered to be active in the study area from mid August 1992–1993) and 12.7 g/h (two fledglings, 1993–1994). At until the end of December and the hours of daylight no time was prey seen being cached by either of the adults available for hunting were 12 h/day from mid August until or the young. mid October, then 13 h/day from mid October until the end of December. This gives a total per breeding season, in a Impact on the local bird community period of 4.5 months (138 days), of 1733 hours available for hunting (observation in this study was for a total of To give a realistic calculation of the impact of the Australian 129 hours). The prey-delivery rates for each breeding Hobbies and their young on the local bird community, season give 988 prey items delivered in 1992–1993 (three 32 Australian Field Ornithology C.G. Morley

Table 5. Prey-delivery rates for a pair of Australian Hobbies at different stages of the breeding cycle over two complete breeding seasons, 1992–1993 and 1993–1994, in Geelong urban parkland: number of prey items delivered per hour (with number of items in parentheses) and biomass delivered per hour (g/h). M = male, F = female, ? = sex unknown; * = female did not hunt in the late nestling period in 1993–1994.

Stage Adult providing prey 1992–1993 1993–1994

No./h Biomass No./h Biomass (g/h) (g/h) Courtship M 0.33 (5) 6.9 0.32 (7) 7.0 F

Incubation M 0.17 (2) 3.7 0.14 (2) 2.8 F

Nestling

Early (F brooding) M 0.48 (4) 18.1 0.98 (5) 38.6 F Late (F off nest) M 0.56 (10) 16.6 1.28 (6) 31.5 F 0.17 (3) 12.6 0* 0*

Total late nestling 0.73 (13) 29.2 1.28 (6) 31.5

Total nestling 0.65 (17) 25.7 1.12 (11) 35.2

Post-fledging: M 0.43 (6) 14.3 0.19 (3) 4.1 F 0.21 (3) 9.3 0.25 (4) 10.1 ? 0.36 (5) 8.9 0.06 (1) 1.25

Total post-fledging 1.00 (14) 32.5 0.50 (8) 15.4

Complete breeding cycle M 0.40 (27) 11.9 0.37 (23) 9.8 F 0.09 (6) 5.3 0.06 (4) 2.6 ? 0.07 (5) 1.9 0.02 (1) 0.3

Total breeding cycle 0.57 (38) 19.1 0.45 (28) 12.7

fledglings) and 780 prey items delivered in 1993–1994 data are available indicate that the Willie Wagtail was preyed (two fledglings, but three and possibly four nestlings), and upon approximately as frequently as would be expected 33.1 kg and 22.0 kg, respectively, delivered in each (1993–1994), and in 1993–1994 the Welcome Swallow complete breeding season. Hirundo neoxena, Zosterops lateralis and Starling At the time of this study, the Sparrow and Starling were taken less frequently than would be expected. were both numerous and common breeding species in the study area and surrounding residential area (Appendix 1; Morley 1983). Juveniles and fledglings of Hunting behaviour both these species were conspicuous when the nestling Hobbies were developing and fledging. The Sparrow and Some hunting behaviour was observed in the nest area Starling, the two most frequent prey species, were the most and nearby (see Table 1 for stages of the breeding cycle). abundant prey species in the parkland during the study, On Day 29 of the 1992–1993 nestling period, at 1045 h, although a few somewhat larger passerines were similarly the female Hobby caught a juvenile Starling in a low flat abundant (Appendix 1). The vulnerability index (Appendix chase through trees within 50 m of the nest-tree. As she 2) indicates that Sparrows and Greenfinches were preyed returned to perch within 8 m of the nest, two other Starlings upon more frequently than would be expected in both briefly harassed her. On Day 33 of the 1992–1993 nestling seasons and Starlings were preyed on more frequently than period, at 1840 h, she unsuccessfully chased a Starling in would be expected in 1992–1993. Other species for which a similar manner in the vicinity of the nest. Avian diet of breeding Australian Hobbies, Geelong, Victoria 33

On Day 6 of the 1992–1993 fledgling period, the male for flying insects at an altitude of two or three times treetop left the nest area and flew in and direct flight to the height, until at least 1918 h when the light intensity was west. He then rose ~20 m and dropped rapidly in what was very low. The female might have returned to the nest at apparently an unsuccessful stoop. 1925 h, though this is uncertain as civil twilight had ended at 1922 h. On Day 12 of the 1993–1994 nestling period at 1818 h, 8 minutes after his return to the nest area with prey that he passed to the female, the male flushed and unsuccessfully Discussion pursued a Starling from the foliage of a Sugar Gum, within 15 m of the lookout-tree. The Starling uttered an agitation Most of the avian diet of the study pair of Australian call, and the Hobby a brief soft chittering kit-kit-kit… as Hobbies and their young was introduced House Sparrows they disappeared out of sight to the north-east. and Common Starlings. This pattern of prey preference is On 12 December 1993 (Day 5 of the fledgling period) at generally similar to the results of studies from Melbourne, 1027 h, after the two fledglings had moved away from the Victoria (Norris 2006) and inland New South Wales (Debus nest area, the female caught a Starling. She chased two et al. 1991; Olsen et al. 2006, 2008), and confirms that or three Starlings, flying together, then singled out one that introduced passerines are an important food source for perched briefly in a pine, but was flushed by the Hobby. the Hobby in urban south-eastern Australia. The avian The Starling perched in a second pine and the Hobby dietary diversity in a purely urban environment was lower then perched beside it, both momentarily side by side. (13 species) than in the study by Olsen et al. (2006, 2008) The Starling flew and was overtaken and captured within for a peri-urban wooded (formerly rural) area (25 species). 20 m by the Hobby, which came from behind and below the Starling in an upward loop. The mean mass of identified avian prey (36 g) in this study is almost the same as that (34 g) found by Debus On Day 8 of the 1993–1994 fledgling period, for a et al. (1991) and similar to that (47–56 g) found by Olsen period of at least 30 minutes from 1244 h, in an area of et al. (2008). The study pair generally captured prey of the parkland ~100 m from the nest-tree, the adult Hobbies ~25 g but also captured prey up to the size of the Starling were involved in skirting along and clipping across the tops (~75 g). This finding is consistent with previous research that of pines, apparently attempting to flush prey. Both Hobbies has concluded that the Hobby’s prey is mostly small birds were using a strong westerly wind to circle upwind and ≤75 g (Marchant & Higgins 1993), with 67% of avian then glide back rapidly downwind. The female, in particular, species “unequivocally recorded as prey of the Australian called loudly and more incessantly than her mate. Typically Hobby” being ≤75 g (Czechura & Debus 1986, p. 193). the ki-ki-ki...call was given more rapidly than usual at a frequency of 9–10 notes per 3 seconds. These calls were As reported by Debus et al. (1991) and Ferguson-Lees uttered at the rate of up to eight sequences per minute. & Christie (2001), the Starlings taken were generally The two were answering each other and the male was juveniles, inexperienced and possibly slower in flight apparently following the manoeuvres of the female. The and less adept at avoiding the Hobbies. They were more fledglings were not seen, but could be heard calling during frequently caught later in the breeding season as the food the last few minutes of this observation period. No prey demands of the Hobbies increased. Many of the Sparrows was taken during this period, though several Galahs, two taken as prey were also juveniles, as were the Willie Magpie- Grallina cyanoleuca and two Red Wattlebirds Wagtail and Crested Shrike-tit. were observed, quickening or deviating in flight to avoid the Two bird species—Crested Shrike-tit and Common area in which the Hobbies were operating. The Hobbies Greenfinch—have not previously been recorded as prey ignored these birds, except on one occasion, when the items of the Australian Hobby. In a study around Berlin, female briefly deviated and half-heartedly followed a Germany, the Greenfinch has been recorded as prey of Magpie-. the Falco subbuteo, making up 6.8% by On Day 30 of the 1992–1993 fledgling period, the adults number of prey items (Cramp 1988). were briefly observed engaged in similar behaviour, rising In each breeding season in the present study, the fledgling and circling high in the wind and then skimming down over Australian Hobbies chased Galahs (~350 g: Higgins 1999) the treetops. About 8 minutes later, the female returned, and Rock Doves (~300 g: Higgins & Davies 1996), both of attended by the male, and passed a plucked and headless which are much heavier than the prey taken by the adult sparrow-sized prey item to a fledgling. Hobbies, and are at the upper limit of prey taken by this The Hobbies usually hunted flying insects by tilting their species (Czechura & Debus 1986; Marchant & Higgins legs forward to catch an insect in the talons, with the body 1993). The fledglings apparently used their vigorous axis vertical. Occasionally, the Hobbies were observed tail-chases of these two species for flying exercise and turning over in flight to catch flying insects. hunting practice. These observations add to the reports in Czechura & Debus (1986) of inexperienced, juvenile or During a 15-minute period on Day 35 of the 1992–1993 immature Hobbies unsuccessfully attacking Rock Doves. fledgling period, when the fledglings were hunting and In common with several other records (Marchant & Higgins capturing flying insects, at least one fledgling (the female?) 1993; Olsen et al. 2006, 2008), the study pair took escaped was hawking for insects and deliberately brushing past the aviary Budgerigars (mostly bright yellow or blue plumage outer foliage of pines. variants). This species is an occasional summer migrant On Day 32 of the 1993–1994 incubation period, at to dry inland areas of Victoria and rarely reaches southern 1905 h (sunset 1854 h), the male flew to the nest and Victoria (Emison et al. 1987). No free-flying Budgerigars relieved the female, which perched and preened briefly, were observed, nor any reported, in the study area during then flew. She was seen overhead several times hawking the study period. 34 Australian Field Ornithology C.G. Morley

In common with earlier findings, the adult Hobbies and Debus et al. (1991) did not observe prey-delivery rates young in this study fed on flying insects such as beetles and during courtship or incubation, and the rates during the dragonflies (Marchant & Higgins 1993; Olsen et al. 2006, nestling and fledgling stages showed no increase. In the 2008). Hobbies also take microbats (Microchiroptera) (e.g. present study, in both seasons, the prey-delivery rate Debus et al. 1991; Aumann 2001; Olsen et al. 2008; Olsen was lowest during incubation, when nutritional demands 2014; Aumann et al. 2016) but these were not detected as were apparently at their lowest. It increased throughout prey in the present study. the nestling stage of each breeding season and increased further in the fledgling period of 1992–1993 (three The prey profile of the Hobbies at Geelong, in terms of fledglings) but decreased to less than half this rate in the the predominance of introduced species, was similar to that fledgling period of 1993–1994 (at least three nestlings but in urban or peri-urban areas at Armidale, New South Wales only two fledglings). (Debus et al. 1991), and Canberra, Australian Capital Territory (Olsen et al. 2006, 2008), but contrasts with the The prey-delivery rates reinforce this pattern, in terms lack of introduced prey taken in the arid zone (Aumann of mass of avian prey per hour, and strongly suggest 2001) and tropics (Aumann et al. 2016), where introduced that at least one, if not two, of the nestlings perished in birds of the size range favoured by Hobbies are not found. 1993–1994, with a figure of 35.2g/h in the total nestling Overall, the prey taxonomic profile (mostly passerines period dropping to 15.4 g/h in the fledgling period in and small parrots) and body-mass profile (prey mostly parallel with reduced brood-size and food demands. By <100 g) are similar across regions and habitats. Insects comparison, the figures for the 1992–1993 season (three seem particularly important as prey in the tropics (Aumann fledglings) showed a slight increase: 25.7 g/h in the total et al. 2016). nestling period and 32.5 g/h after fledging. It is also possible that the prey-delivery rate decreased in 1993–1994 or bad Observed transfer of prey between the adult Hobbies weather might have resulted in one or two nestlings dying. during the courtship, laying, incubation and nestling stages Future studies might involve determining prey-delivery was always at perches—either at the nest or nearby—in rates in mass/time to give a more meaningful indication of contrast with the aerial passes referred to in other studies prey delivered through the breeding season. (listed by Marchant & Higgins 1993). However, late in each fledgling period, some prey transfers were aerial, Debus et al. (1991) observed a significant period during and future studies might confirm whether such transfers the day (0830–1545 h) when no prey deliveries were made. typically become more common as the fledgling period This was not the case in either of the breeding seasons progresses. in the present study, when prey deliveries were made at most times during the day. The earliest prey delivery The data obtained in this study suggest that the male was comparable with that found by Debus et al. (1991), Hobby took larger prey before the female commenced whereas the latest was almost 2 hours later. Future studies hunting than afterwards. When the female was hunting, he might further investigate the spread of delivery times over took relatively light prey, mainly Sparrows, while she took the period from before sunrise to after sunset. larger prey such as Starlings. In common with the findings of a study on the Northern Tablelands of New South Wales This is the first study to attempt to estimate the impact (Debus et al. 1991), the male took juvenile Starlings early of Australian Hobbies on the local bird community. Debus in the breeding cycle when, perhaps, they were easier for et al. (1993) estimated the impact of a pair of nesting him to subdue. Collared Sparrowhawks Accipiter cirrocephalus on a local bird community in northern New South Wales, using two In common with the findings in the review by Czechura different calculations, and found 755 or 800 birds were & Debus (1986), the size of prey taken by the study pair taken over a 4-month period by a pair of Sparrowhawks was within a similar range, considered as a percentage and one female fledgling. The present study gives a similar of Hobby mass. In this study, prey taken by the male was indication of the impact of a pair of small bird-eating raptors in the range 6–36% of average male mass (cf. 5–35%: and young, with estimates of 988 and 780 birds (mostly Czechura & Debus 1986) and 9–26% of average female Sparrows, Starlings and other introduced species) taken by body mass (cf. 3–25%), although the sample size in the the Hobbies for the two 4.5-month-long breeding seasons. current study (n = 10 prey items of the female) is small and In 1992–1993, 33.1 kg of prey was delivered and in a larger sample would be desirable. 1993–1994, 22.0 kg. The calculation of biomass delivered The male Hobby provided food for the female throughout is lower for the second season, even though the calculation the courtship, laying and incubation periods. The female of birds captured is greater, presumably because the prey- began hunting on Day 27 of the 1992–1993 nestling period, delivery rate, used to calculate this figure, dropped so 9 days before two of the nestlings fledged on 5 December. much in the fledgling period. Future studies might usefully The male provided all the food for the female and nestlings investigate the impact of breeding raptors on the local bird community further, as done by Olsen et al. (2008) for the throughout the 1993–1994 nestling period; the female was Canberra area. not observed hunting or returning with prey until the day of fledging. There is some suggestion (Appendix 1) that some The Common Starling (the most abundant) and House prey species, notably the Starling, were more abundant in Sparrow were among the five most abundant bird species 1993–1994 than in 1992–1993, which may explain some in the parkland, and the Silvereye was among the top ten differences in parental behaviour and feeding rates (and (Appendix 1). Others in the top ten, which were not taken possibly initial nestling brood-size) in the two seasons. by Hobbies, are passerines larger than Starlings or agile However, prey abundance was evidently not sustained species that stay close to cover (Magpie-lark, arboreal long enough to enable three nestlings to fledge in Red Wattlebird, Yellow-rumped Thornbill Acanthiza 1993–1994. chrysorrhoa, Common Blackbird Turdus merula), or are Avian diet of breeding Australian Hobbies, Geelong, Victoria 35

larger than a Hobby and dangerous (e.g. Galah, Australian period might have been speculative hunting by the pair, Magpie Gymorhina tibicen). Otherwise, the Hobbies took and more specifically related to defence of territory or pair- less abundant species whose habits or plumage might bonding, as Hobbies do not normally call when hunting have made them conspicuous (e.g. aviary escapee (CGM pers. obs.; S. Debus pers. comm.). Budgerigars), accessible (e.g. grassland Skylark) or Crepuscular hunting, at least 26 minutes and possibly vulnerable (see Olsen et al. 2008; Olsen 2014). 33 minutes after sunset by the female of the study pair, The Sparrow, Greenfinch and Starling were apparently is consistent with the limited information already recorded preyed upon selectively by the Hobbies, perhaps because about the crepuscular (and nocturnal) hunting of the Hobby they were more accessible than other prey species. The (Marchant & Higgins 1993). The method of capturing flying vulnerability indices of the Sparrow and Greenfinch in insects with the talons, by tilting the body forward, was as both breeding seasons show that these species were described by Czechura & Debus (1986). preyed upon more frequently than would be expected from their percentage abundance in the bird community. In This study of a pair of breeding Australian Hobbies 1992–1993, the Starling was preyed upon more frequently over two complete seasons has added new information than expected. These findings need verification, and future and enlarged upon and confirmed many aspects of the studies should measure the abundance (absolute and breeding diet and hunting behaviour of this species in an relative) of prey species in the study area and surrounding urban environment in south-eastern Australia. areas. The fact that the Hobbies almost invariably returned with prey from the south or south-west is consistent with these data for the Sparrow and Starling, both of which Acknowledgements (but particularly the Starling, with flocks of 50+) tended to I thank Rory O’Brien, of Museum Victoria, for the identification congregate to feed on the ground in large open areas in the of some prey samples. Barry Kentish and Denis Jenkins made south and south-west of the parkland, where they could be helpful comments on earlier drafts of this paper. Bill Flentje shared some of the observations late in the 1992–1993 nestling period. flushed and taken aerially by a hunting Hobby. They were Margaret Cameron made helpful comments on several drafts and also common in urban areas that adjoin the parkland to was always a source of encouragement. Stephen Debus assisted the south and west. Greenfinches perched at the top of with a search of more recent literature and final preparation for cypresses in the parkland, to advertise and display, making publication. Two anonymous referees provided constructive them potentially conspicuous and available for Hobbies. comments which improved this article. I also wish to thank my parents, who always encouraged me to look, watch, wonder and Of the native prey species, at the time of the study, marvel at the natural world, and Elizabeth Macpherson for her the White-plumed Honeyeater Ptilotula penicillata, Willie encouragement during the later stages of the project. Wagtail, Welcome Swallow and Silvereye were common species that bred in the parkland (Morley 1983, 1987). The Purple-crowned Lorikeet Glossopsitta porphyrocephala References and Striated Pardalote, visitors to the parkland and Ambrose, S. (1989). Royal Australasian Ornithologists Union surrounding areas, were taken less frequently as prey Australian Bird Count. Royal Australasian Ornithologists Union, than expected from their percentage abundance in the Melbourne. study area. These two species may keep to the foliage Aumann, T. (2001). An intraspecific and interspecific comparison of the larger trees or be more manoeuvrable and able to of raptor diets in the south-west of the Northern Territory, avoid the Hobbies. The Crested Shrike-tit has not been Australia. Wildlife Research 28, 379–393. recorded during 38 years (to December 2017) of regular Aumann, T.A., Baker-Gabb, D.J. & Debus, S.J.S. (2016). Breeding observation in the parkland (Morley 1983, 2017; eBird diets of four raptor species in the Australian tropics. Corella 40, 2017). It is uncommon to rare in urban and suburban 13–16. Cramp, S. (1988). Handbook of the Birds of Europe, the Middle Geelong (Pescott 1983; CGM pers. obs.) but can occur in East and Northern Africa, Volume II: Hawks to Bustards. Oxford urban areas in some river reserves and gardens (Morley University Press, New York. 2015). It might have been a vagrant to the parkland or it Cupper, J. & Cupper, L. (1981). Hawks in Focus. Jaclin, Mildura, might have been taken when the male Hobby was hunting Vic. away from the Geelong parkland. Czechura, G.V. & Debus, S.J.S. (1986). The Australian Hobby Falco longipennis: A review. Australian Bird Watcher 11, In general, the search-and-attack hunting methods 185–207. of the Hobbies observed in the current study were the Debus, S. (2019). Birds of Prey of Australia: A Field Guide. 3rd same as those described by Czechura & Debus (1986), edn. CSIRO Publishing, Melbourne. Marchant & Higgins (1993) and Olsen et al. (2006). The Debus, S.J.S., Ley, A.J., Trémont, S. & Trémont, R. (1991). observation of the female unsuccessfully flushing two or Breeding behaviour and diet of the Australian Hobby Falco three Starlings from a tree and then perching beside one longipennis in northern New South Wales. Australian Bird to catch it as it took off could be considered a variation Watcher 14, 123–137. of landing heavily in vegetation where prey is sheltering. Debus, S.J.S., Ley, A.J., Trémont, S., Trémont, R. & Also, the observation of a fledgling deliberately brushing Collins, J.L. (1993). Breeding behaviour and diet of the Collared past foliage to disturb prey could be considered a variation Sparrowhawk Accipiter cirrocephalus in northern New South of flushing prey from cover. Two accounts of cooperative Wales. Australian Bird Watcher 15, 68–91. eBird Australia (2017). Explore Data – Hotspots – Eastern Park hunting between the adults add to the ‘fast low chasing’ (Geelong). Available online: http://ebird.org/ebird/australia/ summarised by Marchant & Higgins (1993), with the study hotspot/L2549826 (retrieved 12 January 2018). pair sustaining their efforts, on one occasion, for at least Emison, W.B., Beardsall, C.M., Norman, F.I., Loyn, R.H. & 30 minutes, skirting and clipping across the tops of trees Bennett, S.C. (1987). Atlas of Victorian Birds. Department and then banking and gaining height into a strong wind. The of Conservation, Forests & Lands and Royal Australasian behaviour observed on Day 8 of the 1993–1994 fledgling Ornithologists Union, Melbourne. 36 Australian Field Ornithology C.G. Morley

Ferguson-Lees, J. & Christie, D.A. (2001). Raptors of the World. Olsen, J., Fuentes, E., Bird, D.M., Rose, A.B. & Judge, D. (2008). Christopher Helm, London. Dietary shifts based upon prey availability in Peregrine Higgins, P.J. (Ed.) (1999). Handbook of Australian, New Zealand and Australian Hobbies breeding near Canberra, Australia. & Antarctic Birds, Volume 4: Parrots to Dollarbird. Oxford Journal of Raptor Research 42, 125–137. University Press, Melbourne. Olsen, J., Fuentes, E., Rose, A.B. & Trost, S. (2006). Food and Higgins, P.J. & Davies, S.J.J.F. (Eds) (1996). Handbook of hunting of eight breeding raptors near Canberra, 1990–1994. Australian, New Zealand & Antarctic Birds, Volume 3: Snipe to Australian Field Ornithology 23, 77–95. Pigeons. Oxford University Press, Melbourne. Olsen, P.D. (1995). Australian Birds of Prey – The Biology and Hollands, D. (1984). Eagles, Hawks and Falcons of Australia. Ecology of Raptors. University of NSW Press, Sydney. Nelson, Melbourne. Olsen, P.D. & Marples, T.G. (1993). Geographic variation in egg Johnstone, R.E. & Storr, G.M. (1998). Handbook of Western size and clutch size and date of laying of Australian raptors Australian Birds, Volume 1: Non-passerines. Western Australian ( & Strigiformes). Emu 93, 167–179. Museum, Perth. Pescott, T.W. (1983). Birds of Geelong. Neptune Press, Geelong, Loyn, R.H. (1986). The 20 minute search: A simple method for Vic. counting forest birds. Corella 10, 59–60. Price-Jones, H. (1983). Australian Birds of Prey. Doubleday, Marchant, S. & Higgins, P.J. (Eds) (1993). Handbook of Australian, Sydney. New Zealand & Antarctic Birds, Volume 2: Raptors to Lapwings. Rogers, K., Rogers, A. & Rogers, D. (1986). Bander’s Aid. A Guide Oxford University Press, Melbourne. to Ageing and Sexing Bush Birds. A. Rogers, St Andrews, Vic. Metcalf, E.C. (1989). The breeding biology of the Australian Rogers, K., Rogers, A. & Rogers, D. (1990). Bander’s Aid. Hobby Falco longipennis. Australian Bird Watcher 13, 20–29. Supplement One. RAOU Report 67, RAOU, Melbourne. Morley, C. (2015). Geelong Bird Report 2012. Geelong Field Rosalky, D. (2005). Australian Hobbies breeding at the ANU. Naturalists’ Club Inc., Geelong, Vic. Canberra Bird Notes 30, 83–84. Morley, C. (2017). 37 Years of Counting – Building a Long-term Picture. Available online: http://ebird.org/content/australia/ news/37-years-of-counting-building-a-long-term-picture/ (retrieved 12 January 2018). Received 17 June 2018, accepted 17 November 2019, Morley, C.G. (1983). Birds of Eastern Park, Geelong. Geelong published online 23 April 2020 Naturalist 19, 87–114. Morley, C.G. (1987). Birds of Eastern Park, Geelong: Noteworthy breeding events. Geelong Naturalist 23, 104–110. Newton, I. (1986). The Sparrowhawk. Poyser, Staffordshire, UK. Norris, M. (2006). Prey of Hobbies in Melbourne. Boobook 24, 17. Olsen, J. (2014). Australian High Country Raptors. CSIRO Publishing, Melbourne. Avian diet of breeding Australian Hobbies, Geelong, Victoria 37

Appendix 1. Abundance of bird species in the Geelong urban parkland, Victoria, during winter, spring, and summer of 1992–1993 and 1993–1994 using Australian Bird Count (ABC) data: total number of birds per hectare per survey recorded during each of three 2-ha survey sites within the parkland. In each breeding season, each 2-ha site was surveyed three times. √ = species present during study period, but not recorded in ABC surveys, – = species not recorded during study period, + = introduced species, * = prey species recorded as prey of the Australian Hobby in this study.

Species 1992–1993 1993–1994

+Rock Dove Columba livia √

+Spotted Dove Streptopelia chinensis 0.14 0.11

Shining Bronze-Cuckoo Chalcites lucidus 0.03

Masked Lapwing Vanellus miles √ √

Silver Gull Chroicocephalus novaehollandiae 0.21 0.24

White-faced Heron Egretta novaehollandiae √ 0.02

Australian White Ibis Threskiornis moluccus √

Grey Goshawk Accipiter novaehollandiae √

Brown Goshawk Accipiter fasciatus 0.02

Sacred Kingfisher Todiramphus sanctus √

Laughing Kookaburra Dacelo novaeguineae 0.03 0.03

Gang-gang Cockatoo Callocephalon fimbriatum √

Galah Eolophus roseicapilla 0.28 0.24

Sulphur-crested Cockatoo Cacatua galerita √

Crimson Rosella Platycercus elegans √ √

Eastern Rosella Platycercus eximius 0.03

Musk Lorikeet Glossopsitta concinna √ √

*Purple-crowned Lorikeet Glossopsitta porphyrocephala √ √

*Budgerigar Melopsittacus undulatus – –

New Holland Honeyeater Phylidonyris novaehollandiae 0.03

Eastern Spinebill Acanthorhynchus tenuirostris 0.17 0.11

Spiny-cheeked Honeyeater Acanthagenys rufogularis √

Red Wattlebird Anthochaera carunculata 0.66 0.86

*White-plumed Honeyeater Ptilotula penicillata √ √

Yellow-faced Honeyeater Caligavis chrysops 0.03

Spotted Pardalote Pardalotus punctatus √ 0.02

*Striated Pardalote Pardalotus striatus √ 0.03

White-browed Scrubwren Sericornis frontalis 0.09 0.11

Yellow-rumped Thornbill Acanthiza chrysorrhoa 0.47 0.29

Yellow Thornbill Acanthiza nana 0.21 0.21

Striated Thornbill Acanthiza lineata 0.06

Brown Thornbill Acanthiza pusilla 0.08 0.02

Black-faced Cuckoo-shrike Coracina novaehollandiae 0.02 √ 38 Australian Field Ornithology C.G. Morley

Appendix 1 continued

Species 1992–1993 1993–1994

Rufous Whistler Pachycephala rufiventris √

Golden Whistler Pachycephala pectoralis 0.02

*Crested Shrike-tit Falcunculus frontatus – –

Australian Magpie Gymorhina tibicen 0.20 0.35

Grey Butcherbird Cracticus torquatus 0.09 0.03

*Willie Wagtail Rhipidura leucophrys 0.06 0.18

Grey Fantail Rhipidura fuliginosa 0.20 0.08

Little Raven Corvus mellori 0.01 0.21

Magpie-lark Grallina cyanoleuca 0.62 0.87

*+House Sparrow Passer domesticus 0.65 0.56

*+Common Greenfinch Chloris chloris 0.03 0.06

*+European Goldfinch Carduelis carduelis √ √

*+Eurasian Skylark Alauda arvensis √ √

*Welcome Swallow Hirundo neoxena 0.06 0.29

*Silvereye Zosterops lateralis 0.38 0.29

*+Common Starling Sturnus vulgaris 0.63 2.36

+Common Blackbird Turdus merula 0.54 0.66

Appendix 2. Prey of Australian Hobbies in urban parkland in Geelong, Victoria, in the 1992–1993 and 1993–1994 breeding seasons: percentage abundance (A) of prey species for which there are sufficient data, percentage in prey, and vulnerability index (VI: see method). + = introduced species, – = not recorded as prey item in that season so VI is not applicable (na).

Prey species 1992–1993 1993–1994

A % in prey VI A % in prey VI

Willie Wagtail 1.0 – na 2.2 2.1 0.95 +House Sparrow 10.8 28.3 2.62 6.8 28.6 4.21

+Common Greenfinch 0.6 4.3 7.17 0.7 2.0 2.86

Welcome Swallow 0.9 – na 3.5 2.0 0.57

Silvereye 6.3 – na 3.5 2.0 0.57

+Common Starling 10.5 17.4 1.68 28.5 14.3 0.50