Culling farm wildlife for conservation and production on “Koobabbie”, a cereal and sheep growing property, in the northern wheatbelt of Western Australia Denis A Saunders1 and Alison Doley2 1CSIRO Land & Water, PO Box 1700, Canberra ACT 2601 [email protected] Corresponding author: Denis A Saunders 2“Koobabbie”, Coorow WA 6515 Downloaded from http://meridian.allenpress.com/australian-zoologist/article-pdf/40/1/203/2617862/az_2017_046.pdf by guest on 28 September 2021 Koobabbie is a 7,173-ha cereal and sheep growing property in the northern wheatbelt of Western Australia. Unlike most wheatbelt properties that have been extensively cleared of native vegetation, Koobabbie retains 41% of its area under native vegetation. It is listed as an important bird area by BirdLife Australia and BirdLife International, and is a significant part of the region’s conservation estate. Half of Australia’s cockatoo species occur on the property, including the endangered Carnaby’s Cockatoo Calyptorhynchus latirostris. The Major Mitchell’s Cockatoo Cacatua leadbeateri occurs in small numbers on the property, while the Galah C. roseicapilla and Western Corella C. pastinator occur in large numbers, and compete with Carnaby’s Cockatoo and Major Mitchell’s Cockatoo for nest hollows. The owners have been culling Galah and Western Corella since 1997 to reduce competition for nest hollows. In addition, several other species of native animal, and three species of introduced mammal are culled, also for conservation and economic production purposes. This paper reports on the culling, and concludes it is an appropriate part of farm management for conservation and economic production objectives. ABSTRACT Key words: Culling wildlife; killing for conservation; Carnaby’s Cockatoo; Calyptorhynchus latirostris; conservation on farmland. DOI: https://doi.org/10.7882/AZ.2017.046 INTRODUCTION Koobabbie is a 7,173-ha cereal and sheep growing wheatbelt where in some shires over 90% of native property in the Waddy Forest District of the Shire of vegetation has been removed (Jarvis 1979; Saunders and Coorow, in the northern wheatbelt of Western Australia, Curry 1990; Saunders and Ingram 1995). 270km north of Perth, the capital of Western Australia (Figure 1). The property was uncleared when it was With the death of her father, Arnold Ruddock, in 1964, taken up in 1906 by Samuel and Alice Ruddock, the Alison and her husband John took over management grandparents of the current owner Alison Doley1. Since of Koobabbie. Their objectives for Koobabbie have been then it has been developed for broadscale agriculture by ecological and economic sustainability (Doley 1995, three generations of Alison’s family. Samuel contracted 2003). John died in 2007, and Alison has continued tuberculosis in 1914, and spent part of each summer managing the property with these objectives. in Perth or Albany where it was cooler. He did recover sufficiently to ride a horse, and farm until the end of Koobabbie’s farmhouse is located near the centre of the 1948. Samuel’s illness meant Alice played a large part in property at 29056.452’ S; 116012.014E’. Over half of the helping to develop Koobabbie. Samuel and Alice’s vision property, 4,260 ha (59%) is arable. The uncleared native for development was different from that of most farmers vegetation consists of 1,725 ha of salt lake country (see the of that period as they left broad strips of uncleared native western third of the property in Figure 1), 629 ha of rocky vegetation along paddock boundaries, rocky ridges, and ridges, 492 ha of timber belts and bush, and 68 ha of salt drainage lines. Today this difference in the pattern of affected land used for grazing. The timber belts contain clearing can be seen from space (Figure 1), where these morrells Eucalyptus myriadina and E. longicornis, Salmon broad strips and patches of native vegetation stand in Gum E. salmonophloia, Gimlet E. salubris, York Gum stark contrast to the extensively cleared properties of E. loxophleba, and a number of shrub species, including their neighbours, typical of most of Western Australia’s acacias and melaleucas. The remaining native bush consists of a diverse flora, including mallees (Eucalyptus 1 Alison Doley passed away on 20 February 2019. A tribute to Alison, spp,), tammar scrub (Allocasuarina spp.), verticordias, written by Denis Saunders, has been published in Pacific Conservation hakeas, grevilleas, and petrophilas. Biology - https://doi.org/10.1071/PCv25n2_OB Australian 2019 Zoologist volume 40 (1) 203 Theme Edition: Killing for Conservation Saunders & Doley Downloaded from http://meridian.allenpress.com/australian-zoologist/article-pdf/40/1/203/2617862/az_2017_046.pdf by guest on 28 September 2021 Figure 1. Satellite image of Koobabbie showing property boundary, extent of native vegetation and roads. The southern half of the scene appears greener as that part of the image was from a satellite pass at a different season than the northern half. In order to understand the conservation significance of considerably; it is present in the district in the thousands Koobabbie’s native biota, the Doleys commissioned flora (Alison Doley pers. obs.). Galah, Red-tailed Black- and fauna surveys, during which several threatened plant Cockatoo, and Little Corella have expanded their ranges species were identified. Koobabbie has the only known from the arid zone, moving south into the area as a result populations of the shrub Eremophila koobabbiensis and of clearing of native vegetation, provision of cereal crops Tecticornia sp. Coorow, a salt-tolerant succulent plant, and and introduced weeds of agriculture, and establishment of a population of Ptilotus fasciculatus, a herb believed to have water for domestic livestock (Saunders et al. 1985; Saunders been extinct until rediscovered on the property in 1987. and Ingram 1995). Major Mitchell’s’s Cockatoo is near the western limit of its distribution. Carnaby’s Cockatoo Half of Australia’s cockatoo species occur on Koobabbie. is listed as endangered under Western Australian and Galah Cacatua roseicapilla (Figure 2) is numerically the Australian Government legislation, and internationally most common; then in decreasing order, Western Corella under IUCN’s Red List category and criteria (IUCN 2017). C. pastinator (Figure 3), Red-tailed Black-Cockatoo Bird nomenclature follows Christidis and Boles (1994) Calyptorhynchus banksia (Figure 4), Carnaby’s Cockatoo with the exception of Carnaby’s Cockatoo, which follows Calyptorhynchus latirostris (Figure 5), Major Mitchell’s Western Australian Government legislation. Cockatoo Cacatua leadbeateri (Figure 6), and Little Corella C. sanguinea (Alison Doley pers. obs.). Galah, Western Red-tailed Black-Cockatoo, Carnaby’s Cockatoo, Galah, Corella, Red-tailed Black-Cockatoo, and Major Mitchell’s Western Corella, and Major Mitchell’s Cockatoo breed Cockatoo are breeding residents on Koobabbie, while on Koobabbie in large hollows in the remnant woodland, Carnaby’s Cockatoo is a breeding migrant, and Little and in some cases in artificial hollows made of fallen Corella a vagrant (Saunders and Doley 2013). Carnaby’s natural hollows mounted on poles (Figure 7). Saunders Cockatoo, Major Mitchell’s Cockatoo, and Western Corella et al. (2014) reported that in the first decade of this were probably present in the area before development century there were nearly 30 breeding attempts in one for agriculture. Numbers of the first two of these species year by Carnaby’s Cockatoo on the property. Alison has have declined as a result of clearing of native vegetation recorded flocks of up to 34 Major Mitchell’s Cockatoo in the area, but numbers of the last species have increased on Koobabbie. No counts are available for Red-tailed Australian 204 Zoologist volume 40 (1) 2019 Theme Edition: Killing for Conservation Culling farm wildlife for conservation and production Downloaded from http://meridian.allenpress.com/australian-zoologist/article-pdf/40/1/203/2617862/az_2017_046.pdf by guest on 28 September 2021 Figure 2: Male Galah (large carunculations around the dark eye) on the left and female (red eye) on the right (photograph Rick Dawson). Figure 3: Western Corella nestling in a hollow known Figure 4: Red-tailed Black-Cockatoo in flight. Females and to have been used by Carnaby’s Cockatoo (photograph immature birds have black barring on their tails, and adult Rick Dawson). males have no barring on the tail as shown by the bird at the bottom of the photograph (photograph Rick Dawson). Australian 2019 Zoologist volume 40 (1) 205 Theme Edition: Killing for Conservation Saunders & Doley Downloaded from http://meridian.allenpress.com/australian-zoologist/article-pdf/40/1/203/2617862/az_2017_046.pdf by guest on 28 September 2021 Figure 5: Flock of Carnaby’s Cockatoo around a natural hollow. Two males with black bills and red eye rings are at the top, and three females with bone coloured bills, large cheek patches and grey eye rings are lower down. The lowest bird is a female inspecting the hollow (photograph Rick Dawson). Australian 206 Zoologist volume 40 (1) 2019 Theme Edition: Killing for Conservation Culling farm wildlife for conservation and production Downloaded from http://meridian.allenpress.com/australian-zoologist/article-pdf/40/1/203/2617862/az_2017_046.pdf by guest on 28 September 2021 Figure 6: Major Mitchell’s Cockatoo (photograph Rick Dawson). Black-Cockatoo, however they are present in greater (Saunders and Doley 2013), and the full dataset, together numbers than Carnaby’s Cockatoo or Major Mitchell’s