To many, bird watching is a pastimereserved for weekends and retirement.One of north Queensland’s leading birdresearchers makes it a daily event andin the process, has discovered valuableinformation about a shrinkinglandscape.

For the past three years, AngieChapman, a University of QueenslandPhD student, has been working in wetsclerophyll forest - bird watching.

Wet sclerophyll forest describes anarrow band of vegetation which, innortheast Queensland, occurs on thewestern edge of the rainforest above600m. These forests grow in areas ofhigh rainfall where rainforest wouldnormally proliferate but the use of fireprevents the rainforest from invading.Scientists have documented a 50% lossof this forest type during the previous50 years and many are worried that acomplete take-over by rainforest couldlead to the extinction of certain plantand animal species.

With new evidence that rainforests areinvading the wet sclerophyll forests atan alarming rate, scientists are assessingthe impact of rainforest invasion on thewet sclerophyll flora and fauna.

Before Angie’s study, there was onlylimited information available about thebirds of north Queensland’s wetsclerophyll forests.

“Birds in the southern wet sclerophyllforests (NSW and Victoria) are very wellknown, but virtually no informationexisted about the birds in the wetsclerophyll forests of this region,” saidAngie.

Northeast Queensland’s Endangered Wet Sclerophyll ForestsFor the Birds?

November 1998

“I was originally going to focus on asmall number of species, but notknowing what was there in the firstplace made it rather difficult to start thestudy at all,” said Angie, “So thisproject is like opening a book for thefirst time.”

Angie decided to concentrate onforaging behaviour so she could beginto understand how the birds were usingthe vegetation.

Learning about the birds

“I didn’t know which species wereusing wet sclerophyll, let alone whichones might be common,” Angie admits,“or even whether some species wereusing it on a seasonal basis.”

“While watching for birds, I madespecial note of their foraging behaviour.

When birds forage we have absoluteproof they are using the forest and notjust passing through.”

Angie conducted surveys along 2kmtransects in wet sclerophyll forests fromDavies Creek in the north toKoombooloomba in the south. Eachsurvey encompassed varying degrees ofrainforest invasion and differentelevations.

The differences betweengeographically separated species

Why is losing the wet sclerophyll forestin northeast Queensland of suchconcern, when this forest type remainscommon and free from threat in thesouth? Angie argues that in northeastQueensland the forest supports adifferent bird population from thesouthern wet sclerophyll forests.

South of Townsville there exists a drycorridor, called the Burdekin Gap,which acts as a barrier to animalmovement between north and south.As a result, the species in the north areevolving separately from those in thesouth.

Eastern Yellow Robin (Photo courtesy of C and D Frith)

Wet sclerophyll forest - invaded with rainforest

One such species is the Eastern YellowRobin which has a geneticallyequivalent cousin south of the Burdekingap. Although the birds look verysimilar they are recognised as a distinctsub-species.

“I’m especially interested in theendemic and genetically distinct birds,”states Angie. “Is wet sclerophyllimportant to them or not?”

Birds of Wet Sclerophyll Forest

Angie’s hours of “bird watching”revealed that although very few birdscan be called wet sclerophyll specialists(such as the Eastern Yellow Robin), theforest is very important for manyspecies.

“Of the 100 species I recorded in theseforests, one third are either endemic orare recognised as a separate sub-species,” claimed Angie, “The wetsclerophyll forest supports a very richassemblage of birds.”

Eastern Yellow Robins occur mainly innon-invaded wet sclerophyll. Whenforaging they perch on a vantage pointa few metres off the ground and dropdown to retrieve their prey. If the

territory is invaded by rainforest, theground is obscured and foraging isdifficult.

“One of the things I found, is that as therainforest invasion increases, the robinsdecrease” (see Figure 1).

“Therefore rainforest invasion is a realthreat to this endemic sub-species.”

When times are lean in the rainforest

Angie’s work also suggests that wetsclerophyll forests are important forsome birds on a seasonal basis. Thewinter can be a lean time for manybirds.

“The Bridled Honeyeater, is a rainforestendemic and my data show that thebird comes out of the rainforests inwinter to forage in wet sclerophyllforests.”

One commonly occurring tree in wetsclerophyll forest is Banksia integrifolia.This tree flowers in the winter and istherefore a very important nectar sourcefor many birds.

White-cheeked Honeyeaters usuallylive in eucalypt woodland and heathbut in this region, they are confined tohigher altitudes and form a separatesub-species. They rely heavily onbanksia nectar during the wintermonths.

When rainforest invades, banksiacannot germinate under the shade ofthe rainforest cover. Over time, theWhite-cheeked Honeyeater will declineand may not survive in this region.

Wet sclerophyll forest has many insectand nectar eating birds because of thelarge numbers of Allocasuarina sp. andEucalyptus trees. Fruit-eating birdAngie Chapman bird watching

Figure 1: Effect of rainforest invasion onEastern Yellow Robins

species are not well represented in wetsclerophyll forest.

“I believe that the complete loss of wetsclerophyll habitat would spell troublefor some birds and would greatlydisadvantage many others,” declaresAngie. “Fire management is required tocreate suitable foraging areas for theEastern Yellow Robin and allowregeneration of the eucalypts andbanksias upon which many other birdsdepend.”

Diane Daly interviewed Angie for thisstory.

Angie’s list of bird species in wetsclerophyll can be found on the worldwide web at: www.cimm.jcu.edu.au/rainforestCRC/products/infosheet.htm

For more information:

Angie ChapmanCSIRO Tropical Forest Research CentreAtherton, Queensland, Australia, 4883

Phone: 07 4091 8800Fax: 07 4091 3245Email: angie.chapman@tfrc.csiro.au