|Subject:||Little Terns Part 2|
|Date:||Thu, 6 Feb 2003 16:19:14 +1100|
With Brou Lake's closure in early February 2002, last season's favoured Little Tern nesting island has remained submerged and the site devoid of breeding activity…or so we thought! Members of the 'Friends of Brou Lake' group camping on the edge of the lake discovered several nests and three tiny chicks running along the waters edge in late December. Some of South Tuross Head's Little Terns have also dispersed to this site with 18 adults and 8 fledglings recorded on the 31st of January. A successful fox baiting campaign by Bryson Latimer (RLPB) in the preceding few months has definitely helped these birds.
As reported early last season, conditions appeared ideal for Little Terns choosing to nest at the Wallaga Lake site at the commencement of the 2002-2003 breeding season. A combination of the lake's closure and drought conditions causing the rapid recession of water levels exposed enormous areas of potential nesting habitat. Early fox baiting efforts by Bryson Latimer of the Rural Lands Protection Board (RLPB) also significantly reduced numbers of these introduced predators, whilst a series of Bega Valley Shire Council (BVSC) 'Wildlife Protection Zone' signs assisted in creating a 'safe-haven' for these terns.
In mid-December, the 60 adults inhabiting the site commenced their laying efforts and a total of 16 nests containing 37 eggs were recorded. However in the proceeding two-week period all but two nests were systematically predated almost as quickly as they appeared. Interestingly, the culprit is not a recognised predator of Little Terns in NSW. Much to Bill Beaumont's horror, a resident family of three Swamp Harriers was regularly observed scoping the entire area before descending directly upon nests (marked with wooden stakes or not) and devouring their contents!
Following much deliberation we decided to trial a new protective measure. Wire enclosures, not unlike the barriers used to prevent wallabies from feasting on tomato plants, were placed around the two remaining nests. These enclosures are designed to allow Little Terns to both walk-in from all sides (sufficiently sized mesh) and fly-off the nests (the exit hole), yet are not so large as to allow other birds to enter them. This new method appears to have deterred the Harriers as another five nests were subsequently laid raising the total egg count to twelve. Ten chicks have since hatched, seven of which were banded on the 25th of January by Darryl McKay. So our Little Terns are yet again proving to be highly adaptable to recovery initiatives and hopefully some fledglings will result from this site.
Bega Rivermouth (Mogareka)
Last season's fledging number of 40 Little Terns rated the Bega Rivermouth site as one of the most productive colonies in NSW. This outstanding result encouraged volunteers and BVSC and RLPB rangers to make extensive preparations in early November in anticipation of yet another successful season. A temporary fence and scores of interpretative signs were erected on the sandspit and an electric fence was constructed and baiting performed in adjacent Mimosa Rocks National Park to combat the foxes.
With Ron Smith heralding the arrival of the first Little Tern at 8.10am on the 23rd of October and the subsequent appearance of three nests in mid-November all was well on track. That is until several days later when Australian Raven tracks were observed surrounding the scrapes where the eggs had been! An extremely disheartening result for all involved, especially when the 20 or so adults who had been inhabiting the site declined to only several individuals and remained at this level over the proceeding weeks.
However these birds had definitely not entirely disappeared…
Many of Wallagoot Lake's Little Tern adults have since returned to the Bega Rivermouth site to give their offspring a guided tour of their former 'stomping ground'. Up to seven fledglings and 13 adults have been recorded roosting on the rivermouth's edge this month.
We now know that the Mogareka Little Terns were destined for Wallagoot Lake, traditionally a major south coast Little Tern site that has remained inactive over the last couple of years. This season the lake has supplied optimum habitat for the terns, complete with an exposed island free from the often dangerous tidal influence. The rapidly dropping water level has also provided the terns with vast expanses of mudflats (which I'm sure many muddy wardens will contest to!) and easy access to a continuous supply of fresh fish to feed their ever-hungry chicks.
Early November marked the appearance of the first ten or so nests on 'Bird Island', at the northern end of the lake and on the adjacent sandspit. Within weeks adult numbers exceeded 130 individuals and their seemingly unstoppable breeding efforts continued. A total of 109 nests have been laid, with many located a mere 20 centimetres apart. The first chicks hatched in early December and gratefully received the extra branches and driftwood spread on the sparsely vegetated island. The number of chicks scuttling along the waters edge and amongst the added cover has continued to increase, 22 of which were banded by Darryl McKay earlier this month. An enormous 87 fledglings have been recorded to date and although many are now dispersing to other south coast sites, the Wallagoot Lake Little Tern colony continues to be a flurry of activity with 8 eggs anticipated to hatch and 5 chicks to fledge over the next few weeks.
Wallagoot Lake's ideal shorebird habitat is also being enjoyed by a plethora of waterbird and wader species, many of which have been displaced by the inland drought. Furthermore, Fairy Terns have shared the nesting habitat with their Little cousins this season, with at least 15 individuals recorded, many of which tended to nests and chicks.
Overall, a combination of a successful fox baiting campaign by Ross Olsen of the RLPB, the close watch of volunteer wardens and NPWS Rangers for dogs and personal watercraft, minimal human disturbance and the sheer numbers of adult Little Terns (seen combating the predatory efforts of five different species of raptors in one morning!) has deemed the Wallagoot colony an enormous success this season!
Stay tuned for a Hooded Plover and Pied Oystercatcher update
Mike Jarman and Jillian Keating
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