 |
|
2016 Plains-wanderer report Climatic conditions continued to be the main factor affecting plains-wanderers in 2016. The difference in the Southern Riverina in the year just past was that it was too dry (nothing out of the ordinary there) and then it was too wet (no complaints here).
Precipitation Just 42 mm of rain fell on the plains-wanderer property between January and the end of April on an already overly dry plain. From the start of May to the end of September, a massive 305 mm was recorded with the biggest monthly falls in May, August and September; the latter month receiving an incredible 93 mm. From October to year’s end, a further 95 mm was recorded.
There was a great variation in rainfall throughout the district with a disparity of 118 mm between Deniliquin and the plains-wanderer property, about, ‘as the crow flies’, 55 kilometres apart.
2016: how the year played out ... The much higher winter/spring rainfall in the Wanganella area in 2016 saw vegetation return to much of the plains-wanderer country; habitat that had been too bare for plains-wanderers for several years. As the vegetation started to recover in the spring, there was a remarkable influx of plains-wanderers into the district. Where these birds came from is anybody's guess — it’s astounding they were able to come from anywhere at all. Paddocks that had not regularly had plains-wanderers in them for many years were re-colonised.
At the beginning of 2016, we had a small population of plains-wanderers in a single paddock that John and Robert had kept clear of sheep for a couple of years. After four years of below average rainfall, had John and Robert had not implemented this exclusion, there would not have been any plains-wanderers left on the property at this time.
Immature birds that had been bred in the paddock and a few adults were still being seen regularly during January. However, by the end of January, with very little summer rain, the groundcover was becoming decidedly sparse. It became obvious that the plains-wanderers were starting to move and by early February, no plains-wanderers could be found. We went out five times in February and three times in April to a negative result.
Over 30 April—1 May, 18 mm of rain fell on the plains-wanderer property, ending the long dry spell. Then, over 8—9 May, another 39 mm fell. A bird tour operator had booked a plains-wanderer excursion for 12 May. I was not confident we would find a plains-wanderer as I didn't think the vegetation would have had enough time to recover after rain falling so recently. Amazingly, we found an adult male. At least one bird had returned after just one decent rain event and as yet only scant response from the vegetation. What a fantastic little bird!
We imposed a tour embargo to allow the paddock a better chance of recovery after the rain and did not go out again with birders until early September when our own Strzelecki Track outback tour group came through the district. More about that fiasco later …
Rain fell to the tune of 218 mm out on the plains over May and the winter months. This was probably the best winter rain we have had since the 1990s.
On 29 August, John and I did some reconnaissance for the upcoming outback tour. We found a breeding pair within fifteen minutes. (You might think that would auger well for the outback group’s prospects. You’d be wrong!).
In the first days of September another 20 mm of rain fell out on the plains, causing the paddock to be saturated — to the extent that we couldn't drive on the paddock on 3 September. On that evening, at dusk, I walked our outback tour group in to the locality where we had seen the pair the previous week. Right on cue, the female plains-wanderer started calling. 'Beauty', I said to myself, 'we'll get her!'. Dark clouds were on the horizon, literally and metaphorically. As we got within 50 metres of the calling female and were waiting for it to get a little darker, a storm hit. We got drenched. The plains-wanderer stopped calling and we were unable to find her in the ensuing mayhem. We headed for Deniliquin while we still had some traction with the road out to the highway. (While this was happening, Trisha had set up dinner in John’s shearers’ quarters. She packed up quickly and tried to get out. Too late, she got bogged. John, bless him, managed to get back to his shed, got his tractor and pulled Trisha's 4WD out. To rub salt into the wound, while Trisha was up to her axles in mud, I had to find somewhere to eat, late on a Saturday night in Deniliquin, with a wet, hungry, disgruntled group. Happy days!).
It continued to rain in September with 93 mm recorded on the plains-wanderer property. It was now so wet that the plains-wanderers were flooded out of the paddock we had been finding them in. On 25 September, we heard at least two calling females in another paddock. Walking out with torches, with effort and luck, we found one of them. This was the only way we could find plains-wanderers in the following weeks. With all the wind and rain we were getting, it was not easy and we had four misses in September although females were sometimes heard calling. Despite the very wet conditions plains-wanderers were still attempting to breed. If the females were laying, nests were most likely being flooded at this stage.
In early October, a black falcon and a spotted harrier were occasionally seen hunting together out on the plains. Their M.O. was that the spotted harrier hunted low over the plains and the black falcon followed up above. Anything the harrier flushed could be dived on by the falcon and if the falcon missed, the harrier got another go at it. Few birds would have escaped this powerful partnership. The odd duo was seen on one occasion sitting on a fence near John’s house, about 150 metres apart. As we watched, the harrier took off and landed right beside the falcon, seemingly the best of friends.
The spotted harrier partially built a nest in the box clump near John's house; however, as it didn't appear to have a mate, it came to nothing.
Around this time, John found the legs and feathers of an adult female plains-wanderer under a dead tree at the rear of his house. We don't know which bird-of-prey was the successful predator but where John found the legs and feathers was a more likely spot for a black falcon to have plucked and eaten its prey than a spotted harrier. While the identity of the predator is uncertain, it is likely that neither would have carted the plains-wanderer all the way back to John's house from the paddock where we were finding plains-wanderers, which was over five kilometres away. What it did signal was that plains-wanderers were probably present again in the large paddock around John's house where we had not had them regularly since they were flooded out in 2010. However, it was still too wet to access that paddock.
With a hiccup here and there, we continued to find plains-wanderers in October in the second paddock that we had found them in on 25 September. The rain persisted until around 6 October. By 12 October we could drive on the second paddock and found a courting pair of plains-wanderers that evening.
On 4 November and 20 November, we located an immature female, both about three months old. I am unsure if these two birds were bred on the property or if they came from further afield. It’s possible that they bred on the property before it became very wet in September.
A nest with four eggs was located on 7 November and another on 29 November in the paddock we had been seeing plains-wanderers back in late September/early October. On the first occasion, I found the nest while I was looking for inland dotterel and on the second I was doing some reconnaissance on my own for plains-wanderer. On this latter occasion I also recorded a male plains-wanderer in the late afternoon, back in the original paddock they had been flooded out of in early September. This made it three different paddocks we had plains-wanderers in (and by year’s end we had found them in a fourth paddock).
By early December the females had largely stopped calling west of John's house and they became much harder to find. I was expecting at this time to see some males with chicks in this paddock but could find none. They didn't appear to have any breeding success here, however, it is a big paddock (about 1500 ha) and there was a fair amount of cover on it, so it is likely we missed chicks.
We know there were at least two successful clutches for the 2016 season as we found chicks in the paddock where I had found nests in November: On 8 December we located a juvenile, probably a male about two months old, and on 22 December an adult male with four almost full-grown young about six weeks old. Two of these chicks were again seen on 28 December, independent of dad.
We recorded about ten different females on the plains-wanderer property in the spring/summer of 2016 and undoubtedly there were others we did not find. This is the highest number of breeding birds we have had on the property for many years, possibly since the late 1990s and early 2000s. Despite this, we had more dips this year than any year since we started searching for plains-wanderers in the 1980s. A failure rate that reflects the drought conditions prevailing at the front end of the year and the glorious but thwarting rain of early spring.
Despite the high number of females present they do not seem to have bred as well as we had hoped, particularly compared to last year when we recorded about four clutches of young from a smaller number of females. However, this year they were spread out over a much larger area and there was more groundcover, making them more difficult to find. So it is entirely possible there was greater breeding success than our observations suggest. It will be interesting to see how many juveniles we find in the first few months of 2017.
Acknowledgements As always, there would have been no plains-wanderer searches without the incalculable support and assistance of the Nevinson family. The depth of that support was demonstrated when Robert, co-leading a plains-wanderer weekend in the spring, had to, as brigade captain, go and fight a fire. John, at death's door with pneumonia, came out to replace Robert as co-leader. He probably got pneumonia rescuing Trisha when she got bogged down at his shearing quarters during that stormy, stormy night of the outback tour.
Summary of 2016 plains-wanderer search stats The drought conditions of 2012, 2013, 2014 and 2015 carried over into 2016 and continued until May when rain started to fall. We then had respectable rainfall totals each month until the first week in October. There was a game changing total of 93 mm in September. Both climatic conditions of drought and flood wreaked havoc with our searches for plains-wanderers in 2016. Still, we will take the wet over the dry every time.
|
