Saturday, July 24, 2010

Welcome Winter Visitors

One of the delights of Winter in many urban gardens in Tasmania, is the arrival of honeyeaters to feed on the array of "exotic" native plants that flower at this time of year. As I sit typing this story, I can hear the unmistakable "jik" call of a Crescent Honeyeater, just outside the window. It's there to feed on the red flowers of a callistemon (bottlebrush), now unfortunately showing its' 40 years plus, and beginning to slowly die. Every now and then, I try my hand at photographing them. I say them, but in truth, I've no idea how many visit, rarely seeing more than one at any one time. They do seem to have a routine, arriving via a closeby dense shrub, and warily watching for some time before showing themselves. The male Crescent Honeyeaters then usually announce themselves by singing, before partaking of the pollen. The females, with their relatively subdued plumage, slink in, trying to stay as unobtrusive as possible, largely because if a male Crescent sees them, they'll be chased off.
Another unobtrusive visitor, far fewer in number, are the Eastern Spinebills. In fact, it was only while trying to photograph the Crescents that I realised that they are regulars too. Difficult to photograph at the best of times, with their hyped up behaviour with constant flicking of wings and tail, the image at top is the only worthwhile shot I managed in several attempts.
Every once in awhile, a flock of Silvereyes will descend on the garden, their arrival preceded by the constant "tang tang" call that keeps the flock together. I counted at least 30 birds in one arriving flock, feeding on both blossom and insects, mainly whitefly and greenfly.
Welcome visitors to me maybe, but their arrival, if spotted, is anathema to the resident Little Wattlebirds. With much snapping of bills, they plough into the shrubs holding the visitors, and chasing them with considerable vigour, when they take flight.
Since I started this story a month has passed and I realised if I didn't publish it soon, Spring will have sprung, and I think maybe it already has. On a recent visit to Risdon Brook Park, I heard then saw 2, almost certainly a pair, Fan-tailed Cuckoos, seemingly on the prowl, and at Peter Murrell Reserve, I heard a Horsfield's Bronze-cuckoo calling. With the continuing dry weather here in the south-east of Tasmania, together with sunny days, one might be forgiven for believing that Spring has indeed arrived. But I don't think we've quite down with Winter yet!

Sunday, July 11, 2010

Little Tassie Battler..........40Spotted Pardalote

A recent article in Wingspan (Birds Australia's magazine) highlighted the plight of the Forty-spotted Pardalote, a species endemic to Tasmania. In essence, the article showed that there has been a marked decline in numbers, from an estimated 3,520 birds in 1986-7, to only 1500 or so in the latest survey, conducted in 2009-10. This iconic Tasmanian bird, one of our smallest species, has long been on the endangered list.

40spots are around 10cm in length and they spend much of their life in the outer canopy of eucalypts, and anyone who has looked for them knows just how difficult they can be to find. Probably never numerous, they're found mainly in White Peppermints Eucalyptus viminalis, known as Manna Gums, a species naturally found along the coasts of south-east Tasmania. Colonies are found mainly on Maria and Bruny Islands and on the Tinderbox Peninsula south of Hobart.

The article speculates the reasons for the decline, suggesting climate change, drought and die-back disease in eucalypts.

In recent years I and many visiting birders, have looked and found them in the Peter Murrell Reserve at Kingston, south of Hobart. During my visits this last autumn, I have only occasionally seen them there, and always at the same location. To be fair, I haven't made a point of looking for them, and only found them because I heard them calling. But my overall impression is that there are very few about, and this impression is typical of other birders experience.

I am not a biologist, but my concern is that we seem to know surprisingly little about these birds. It's well known that a major food source is "manna", the conical scales spun by lerp species on the underside of eucalypt leaves. These sugary scales are known as honeydew, and are also eaten by a range of birds, including Black-headed, Yellow-throated, and Crescent Honeyeaters. These lerps are considered a pest as they skeletonise the leaves, which in turn can have an impact on the wellbeing of the tree. My observations locally suggest that there is a paucity of these insects on eucalypts this winter, so is this the "x factor"? Two winters ago the numbers of lerp 'infested" trees was considerable, and many Striated Pardalotes overwintered rather than migrate to the Mainland as they normally do. Were the numbers of lerps the reason?

Obviously the above is just my observations, and only in a small area of the state, but to my mind it does highlight some of the gaps in our understanding of what makes pardalotes 'tick'.

A much greater effort needs to be applied to the wellbeing of the 40Spot and soon. The degrading of the Peter Murrell Reserve, with ever more recreational activity and industrial and housing development on the surrounds, suggests that we're not taking this issue seriously. A more proactive approach is called for.

NB. The accompanying images were taken at the Peter Murrell Reserve about 2 1/2 years ago. I noted that these birds were regularly coming down to a bush on the side of a hill, and was grateful for a relatively easy chance to photograph them. I surmised they might be feeding nearby young, but they didn't appear to be carrying food and were unfazed by my presence. I moved away to better understand what was going on. They were in fact visiting a nest site situated behind a thick piece of bark near the base of a Manna Gum. Further watching revealed that the visiting birds were mainly juveniles, and that a family of 40spots appeared to be using this as a "funk" hole.