REPORT ON ABNL BIRD WEEK 2010

By Dr Richard Noske

The 2010 Bird Week at ABNL was certainly different to those of the previous two years, reflecting the importance of the monsoonal rains on the flora and fauna of the region. The last wet season (November 2009 to May 2010) saw exceptionally high rainfall in January 2010 (607 mm), over double the average for this month, and almost double the average rain for April (153 mm). Maningrida’s mean annual rainfall is approximately 1300 mm, and although Darwin is a lot wetter (1700 mm), the wet season at Maningrida is more protracted, with May experiencing higher rainfall than in Darwin*. During the last wet season Darwin (airport) had an atypically protracted wet season with high falls in April and exceptionally high falls in May, but also had good rain in the early wet season, resulting in the wettest wet season in a decade.

As a result of the good rains during the late wet season, the landscape of the Maningrida region was exceptionally green for the annual early dry season Bird Week. The grass was too uncured to burn on several floodplains, making parts of the Tomkinson floodplain inaccessible to our vehicles due to dense tall grass cover. The boggy run-on areas en route to Kubumi prohibited our usual trip to the rock art sites, with the result that an alternative site had to be used to see sandstone birds. Due to abundance of standing water, many billabongs were still covered in dense tall spike-rushes, reducing opportunities for viewing some wetland birds (eg. Magpie Geese, Jacanas). On the Tomkinson floodplain, numbers of Red-tailed Black Cockatoos were lower than usual for Bird Week, doubtless due to the lack of burnt areas exposing seed on the ground, but the abundant seeds on standing grasses attracted many Chestnut-breasted Mannikins.

The highlight of the week was undeniably the NT-endemic Hooded Parrot, of which up to 36 were seen on the margins of the Tomkinson floodplain, within 1 kilometre of the Lodge as the crow flies. Although pairs or small flocks of this species had been sighted by bird guides in previous years, they were apparently more mobile than this year’s flock, eluding the guests. In contrast, this year’s “Hoodies” stayed in the same vicinity for at least four days, favouring the area where the recently burnt plains with magnetic termite mounds abutted the unburnt low paperbark woodland with its tall grasses. But “Hoodies” may have been quite widespread, as the brief sighting of a pair near the culvert on the Gunbalanya road indicated.

Although Gouldian Finches were seen by all, their numbers were low compared to previous years, the largest flock being of 10(?) birds on the Tomkinson floodplain. Curiously, numbers of Long-tailed and Masked Finches also seemed a lot lower than normal, suggesting that the unusually wet condition of the country was having a deleterious effect on local populations, probably through inaccessibility of seed banks due to the dense grass cover and/or delayed seed production of certain grasses. Higher up, flowering paperbarks dotted around billabongs and on the floodplains (notably the smelly wattle-flowered paperbark Melaleuca acacioides) attracted good numbers of the usual honeyeaters, including the mobile Banded Honeyeater and Rufous-throated Honeyeater, but numbers of Varied Lorikeets were low compared to previous years due to the lack of flowering by eucalypts (<10% of the two common species). As expected at this time of year, resident White-throated and Yellow-tinted Honeyeaters were breeding, fledglings being seen on several occasions. A male Northern Shrike-tit, one of the Top End’s rarest birds, was eventually tracked down by a small group of persistent die-hard birdwatchers, after countless attempts by the author to call them up the species in many of the known territories of this remote population. 

Moving to marine birds, the sand cay and the mouth of the Blyth River were exceptionally productive, “terning” up no fewer than eight species of terns. In addition to the usual thousands of Bridled Terns on the island, there were at least 500 Roseate Terns, mostly in non-breeding/ immature plumage, but including around 15 pairs of bright red-billed birds that appeared to be in a courting mood. The island also hosted one Black Noddy (three, last year), and the beach some recently fledged Little Terns being fed by their parents. The mangroves were also very productive. Chestnut Rails were seen by all, and one boat ride chalked up no fewer than six “chooks” in less than 2 hours, one pair provided sustained views and an exceptionally rare opportunity to see these birds giving their inimitable donkey-like calls, in which two birds duetted with their bodies erect, chests almost touching and bills raised. 

All in all, another successful Bird Week, with happy faces all around! Thanks again to the Dave Thomas, Marc Besnard, Mick, Chris and Haley, and of course, Alex Julius, for making it all possible.

Richard Noske
10 July 2010

*As well as being wetter, Bird Week 2010 was warmer. Minimum temperatures for the first week of July averaged 5 degrees warmer (22°C) than the same period last year and the average for the previous 40 years (17°C), while relative humidity at 09:00 hrs was almost 10% less than last year and the long-term average. Winds at 09:00 hrs averaged 23 km per hour (12 knots), which is 5-10 km per hour stronger than last year, making sea travel a bit less comfortable.