2015 Plains-wanderer annual report

2015 PLAINS-WANDERER REPORT As in 2014, low and erratic rainfall put plains-wanderers under pressure in the Wanganella district in 2015. Throughout the district, the rainfall was again 50—100 mm below the long term average and crucially, this is the fourth year in succession of below average rainfall.The rainfall varied throughout the district, with Wanganella township recording 329.9 mm, whereas out on the plains-wanderer property only 267.5 mm fell, a difference of 62.4 mm in only about 40 km. Even within the combined plains-wanderer properties, the rainfall varied by up to 75 mm in a short distance. Over the past 15 years, 11 have been droughts or had well below average rainfall, two have been a bit above average and two have been flood years —in itself, problematic for plains-wanderers. In such bleak conditions, no bird could be expected to thrive, nor can they co-exist with livestock when cover is so scarce. This is reflected in the fact that in 2015 the only paddock that still contains plains-wanderers has had little or no stock in it over the past three years. As over the past 15 years, the irregular rainfall continued in 2015 with severe deficits in February and March (no rain at all was recorded in March), May, September, October and December. The September and October deficits were the most crucial, coming in prime breeding time for plains-wanderers and most other species. During the year we had three two-month periods of little rainfall: February/March, September/October (except for 31 October), and after the first week of November through to the end of December. Despite all these hardships plains-wanderers still managed to breed successfully in 2015 (much to the Nevinson family’s credit in these dry years when feed is scarce). The year got off to a good start with well above average rainfall in January, which triggered breeding. An adult male with two small chicks was recorded in mid February and a courting pair on 23 February. Immature birds (three to five months old) were recorded in January, March and April. During this period of time, we suspect we had at least two adult females (each probably with two males) as well as up to four immature birds present in the one paddock. By May, numbers had dropped off considerably and only a single male could be located on 25 May. By late July, when we next looked for plains-wanderers, they had seemingly disappeared. Despite looking for them on four occasions in late July and in August, only a single male was located in an area that appeared marginal at best and it was not seen there again. With only minimal cover, the situation appeared dire. After several nights’ reconnaissance, including two nights searching a neighbouring property, with no positive result, we were worried; then, on our last attempt in late August, a male with small chicks was found. This meant he had been on eggs back in July as plains-wanderers take 26 days to hatch. This was an amazing effort as there was very little cover out on the plains at that time. On 18 September, an adult female was located, the first seen since April. By mid October, there was thought to be a second adult female present and probably each female had two males each. By late November, a third female was possibly present given where they were located in the paddock. However, it was difficult to be certain as the maximum number of adult females seen in any one night was two birds (29 November). As in the previous year’s low, erratic rainfall, breeding was again attempted whenever conditions appeared even marginally favourable. Breeding birds were detected in January, February, August (eggs in July), September, October and November. One young female, about three months of age, was recorded on 24 October, calling for a mate, demonstrating that the species can breed at a very young age. Clutches of chicks were seen in February (male with two chicks), late August (male with two to three chicks), November (male with five chicks that subsequently lost one, with only four chicks seen 12 December) and another in December (male with one chick — different male/chick to 12 December sighting). In early December some immature birds were seen that did not match up with any of our known clutches so it was thought that another clutch had been raised nearby that we had not detected. It seems likely that five clutches of chicks have been raised in this paddock over the twelve-month period, albeit, two of these clutches had only two and one chicks. It is also not known how many chicks made it to independence. The clutch of five chicks was a mighty effort in such bleak conditions and was in much the same locality as the five chicks recorded in 2014; it’s possible the same adults could be involved. Quite a few of the earlier clutches have made it through to independence, going by the number of immature birds recorded in October, November and December. From September through to December 2015, up to 20 plains-wanderers including chicks and juveniles were estimated to have been in the one paddock. Climate change and associated extreme weather events are the overriding causal factors limiting the plains-wanderer to very low numbers. The species is hanging on but only just. The problem it has at present in the Wanganella district is there is nowhere for population expansion, with all the surrounding country too bare for them. Unless we have a reasonable rainfall this year, plains-wanderers will again be restricted to small, ungrazed or lightly grazed areas. Any surplus birds will have to move quite some distance to find suitable habitat, if they can find any at all. Stats In 2015, Robert and/or I went out spotlighting for plains-wanderers with clients on 56 nights (43 in 2014). The number of clients including Australian and international birding tour leaders totalled 241 birders (196 in 2014). We had 50 successful outings with a total of 230 happy clients. Six searches with a total of 11 clients failed to find a plains-wanderer, the same number of search failures and disappointed clients as in 2014. Four of these failed searches occurred in late July and August, and two in October. Robert and/or I did three or four reconnaissance trips, of which one was successful. All plains-wanderer searches are documented on the Latest News page of our website. http://www.philipmaher.com/LatestNews1htm.htm Philip Maher Australian Ornithological Services Pty Ltd Deniliquin 2710 New South Wales www.philipmaher.com[1]  Links: —— [1] http://www.philipmaher.com