Category Archives: Pardalotus

More than a supermarket in Coober Pedy

Balwyn meeting 25 August 2015
Member’s topic

Recently Birdlife Melbourne members, John and Trina Young got some big ticks in Coober Pedy. After weeks of looking for target species in northern Australia with low success, they were returning on the Stuart Highway. With some time to spare in Coober Pedy, and staying faithful to The Complete Guide to Finding the Birds of Australia by R. Thomas & S Thomas, they drove the 18km northwest to the breakaways. Walking in this area they saw Spotted Harrier, then a Golden Chat and then Gibberbirds; many of them. After that success, the following day they went 12km southeast on the highway to, horror of horrors, the free camping area at the Hutchison Memorial. About 100-200 metres away from the caravans, Winnebagos, dogs and children, in the recommended bird site, they spotted Pied Honeyeater, Crimson Chat and then, my nemesis, Chestnut-breasted Whiteface. So as John put it, a halt in Coober Pedy was worth far more than a bag of groceries from the supermarket. Thanks for this tip off, John.

Chestnut-breasted Whiteface near Strzelecki Track by Ron Knight. From Wikipedia
Chestnut-breasted Whiteface near Strzelecki Track by Ron Knight. From Wikipedia
Note on birding etiquette

John also left us with a worthwhile reminder to always check with the owner or manager of private property before wandering about looking for birds. It’s a sad fact that bird watchers are no longer allowed on some stations. There’s no excuse in the bush; everyone knows everyone, so go to the hotel, service station, post office or the neighbour. Get a phone number and call first or call at the homestead.

Contributor: Daphne Hards

A cagey business

Nest cages – Help or hindrance to a breeding shorebird population?
PhD Candidate Laura Tan reports on the pros and cons of predator exclusion cages around nests

Southwest of Melbourne at Truganina and Cheetham Wetlands, a population of Red-capped Plovers (Charadrius ruficapillus) has been studied by a research team (led by Dr Mike Weston) at Deakin University’s Centre for Integrative Ecology since 2008. The Red-capped Plover is a ground-nesting bird that lays up to two 3cm long eggs in a shallow scrape in the ground. They rely primarily on crypsis (camouflage of the egg and incubator) and cover (e.g. vegetation) to keep eggs safe over a 30-day incubation period. The species is widespread throughout wetlands in Australia, however in some areas habitat changes confine the species to isolated habitats with high predator densities.

Flagged Red-capped Plover male. Photo by Daniel Lees. If you see any RCPs with engraved leg flags, please let us know: mike.weston@deakin.edu.au or for all other flagged species: flagging@awsg.org.au
Flagged Red-capped Plover male. Photo by Daniel Lees. If you see any RCPs with engraved leg flags, please let us know: mike.weston@deakin.edu.au or for all other flagged species: flagging@awsg.org.au

When monitoring first began, it became increasingly clear that hatching and fledging success was very low – most eggs were preyed upon before they hatched, with foxes and ravens being the key egg predators. The low reproductive success recorded probably meant the viability of the population was in question.

Deakin University Wildlife and Conservation Biology researchers have the dual aim of contributing to science and also developing and testing conservation solutions for our study animals. We investigated the use of predator exclosures, or ‘nest cages’ (cage-like structures placed surrounding a nest, allowing entry and exit of the incubator but excluding both larger mammalian and avian predators) as an option to reduce the rate of clutch predation. Despite use in other management programs, the present literature is conflicted as to whether nest cages actually help target populations. Nest cages can potentially be used to buy time while longer-term solutions are implemented, and if effective, would be valuable if they could be extended to threatened species. However, downsides are that the nest location is basically advertised once a cage is installed, thus predators may ambush incubating birds or chicks as they leave the security of the cage, or nests could even be abandoned. Furthermore, it is a time-consuming option, requiring a large ongoing search and caging effort.

Female Red-capped Plover and a newly hatched chick inside a nest cage
Female Red-capped Plover and a newly hatched chick inside a nest cage

For the last three breeding seasons we have placed cages over 117 nests of 202 located. During the first season (2012-2013) we compared caged with non-caged nests, and found that caged nests had an overwhelming influence on hatching success (at least one egg hatched at 96.2% of 26 caged nests, versus 6.8% of 44 uncaged nests); of all caged nests, only one cage appeared to have been compromised (for full results see http://tinyurl.com/RCPexclosures2015). Abandonment was slightly higher at caged nests (28% versus 10% at non-caged nests); though this may have been because clutches were surviving long enough to allow abandonment to occur.

Remote sensor camera placed near a nest cage
Remote sensor camera placed near a nest cage

The following two seasons we continued to use nest cages. With the initial comparison study complete, we began caging all nests and placing remote sensor cameras nearby. This was to help determine:

  • how many and what predators were visiting nests;
  • potential causes of abandonment; and
  • to learn more about Red-capped Plover behaviour during incubation and after hatching of eggs (chicks can leave the nest within 24 hours of hatching) in conjunction with nest cage use.

The footage from our first nests revealed a lot – numerous visits by ravens and foxes, and suggestions of predation on an incubating parent by a raven. This footage revealed the possibility that there may have been more adult mortality than previously recognized when using cages. Since then, we have recorded various levels of suggestive evidence of other adult deaths at nests, with ravens and foxes as culprits. In the last season, we obtained unambiguous evidence of a fox ambush of a male incubator at a cage, and a raven ambush of chicks as they leave the cage. In particular, from a population viewpoint, mortality of an adult bird is an especially concerning matter (as adults have long reproductive potentials), and an important consideration in the use of nest cages.

Ravens trying to breach a nest cage
Ravens trying to breach a nest cage

It is hard to recommend or dismiss the use of nest cages in predator management programs entirely. However, if a population is suffering due to high egg depredation, the use of nest cages should be considered given the high rate of hatching success. Despite this, it’s unlikely that nest cages confer a huge benefit over not using them, but in conjunction with other predator management methods, it has the potential to be a very successful option.

Red-capped Plover chicks successfully hatched from a nest cage
Red-capped Plover chicks successfully hatched from a nest cage

Many thanks to Parks Victoria and the Point Cook Coastal Park rangers for so kindly allowing us to continue our research on this wonderful species. Funding was provided by the M.A. Ingram Trust, the Australian Government’s Caring for our Country via BirdLife Australia’s Beach-nesting Birds Program, the Hermon Slade Foundation, Australian Bird Environment Fund (BOCA), Ecology and Heritage Partners, Theiss Degremont Joint Venture and AquaSure.

Our current publications from this study include the following

Ekanayake, K.B., Weston, M.A., Nimmo, D.G., Maguire, G.S., Endler, J.A., Küpper, C., 2015. The bright incubate at night: sexual dichromatism and adaptive incubation division in an open-nesting shorebird. Proceedings of the Royal Society B, 282: 20143026.

Tan, L.X.L., Buchanan, K.A., Maguire, G.M., Weston, M.A., 2015. Cover, not caging, influences chronic physiological stress in a ground nesting bird. Journal of Avian Biology, 46: 001-007.

Weekdays Outing Report – Hallam Valley Road

The weather forecast read the previous week was dismally ‘cold, wet, windy’, but the day was sunny, breezy and cool so 15 of us assembled with binoculars and cameras. Rob Grosvenor led the group in a walk around the ponds. The area is one of the Melbourne Water flood retarding basins which are surveyed monthly by BirdLife Melbourne volunteers.

Pond within Industrial zone. Photo by Diane Tweeddale
Pond within Industrial zone. Photo by Diane Tweeddale

It is interesting to record the birds found in such a small, recently established space among an area zoned light industrial and commercial. Birds here clearly survive despite potential disturbance. Clumps of gorse or reeds sheltered Superb Fairy-wrens, Common Greenfinches and Red-browed Finches while some lucky early arrivals recorded a silent Golden-headed Cisticola. New Holland Honeyeaters dominated but there were White-plumed Honeyeaters in some areas including a stand of eucalypts. A few Red Wattlebirds were recorded and a highlight was three Spiny-cheeked Honeyeaters at the eastern end of the basin.

Spiny-cheeked Honeyeater. Photo by Stephen Garth
Spiny-cheeked Honeyeater. Photo by Stephen Garth

Jokes about a ‘duck-free wetland’ fell silent at the eastern ponds beside the go-kart circuit where Grey and Chestnut Teal, Australian Wood and Pacific Black Ducks joined two Great Egrets, several Eurasian Coots, a Dusky Moorhen and a Black-fronted Dotterel.

Great Egret. Photo by Stephen Garth
Great Egret. Photo by Stephen Garth

Other waterbirds included a male Australasian Darter, Little Pied and Great Cormorants, an Australian Pelican, a White-faced Heron and a passing Straw-necked Ibis.Raptors were clearly doing well as we saw Black-shouldered Kite, Nankeen Kestrel, Swamp Harrier and Brown and Peregrine Falcons. Rock and Spotted Doves, Common Bronzewing and Crested Pigeon were also present.

Nankeen Kestrel. Photo by Stephen Garth
Nankeen Kestrel. Photo by Stephen Garth

The final species count was 49; rather satisfying for a winter’s day in a small, much altered area and we thanked Rob for showing us the potential of the site.

Diane Tweeddale coordinator BirdLife Melbourne Weekdays Outings

Weekdays Outing to Three Chain Road

11 May 2015

Though the weather had been wet and windy we were fortunate to encounter clouds and sun and a mostly calm day. The crowd numbered 25 and John Prytherch organised us to alternately drive and walk along the road.

The wide road reserve formed the backbone of our walk but adjacent plantings and remnant scrub in the paddocks were extremely productive.

We met beside a small dam where Dusky Moorhen and Little Pied Cormorant started many people’s list. Sulphur-crested Cockatoos were noisy overhead and Yellow-rumped Thornbills foraged near the fence line until the farmer appeared with a pair of dogs.

Scarlet Robin male. Photographer: Marilyn Ellis
Scarlet Robin male. Photographer: Marilyn Ellis
Scarlet Robin female. Photographer: Stephen Garth
Scarlet Robin female. Photographer: Stephen Garth

The highlight here, however, was a male Scarlet Robin. There were five stages in today’s walk and we added species at each. Grey Shrike-thrushes made their single piercing winter call and a Wedge-tailed Eagle flew overhead.

Buff-rumped Thornbill. Photographer: Kathy Zonnevylle
Buff-rumped Thornbill. Photographer: Kathy Zonnevylle

Spotted Pardalotes were heard but seldom seen while a male Golden Whistler delighted some. An unprepossessing stand of spindly eucalypts stood over a litter of shed leaves. It contained male and female Hooded Robins, at least one female Flame Robin, several Jacky Winters and a Brown Treecreeper.

Jacky Winter. Photographer: Marilyn Ellis
Jacky Winter. Photographer: Marilyn Ellis

Another spindly stand added male Flame Robins, Scarlet Robin and an Eastern Yellow Robin. Much discussion ensued after very brief sightings of raptors.

Grey Fantail. Photographer: Kathy Zonnevylle
Grey Fantail. Photographer: Kathy Zonnevylle

A later visit by an unmistakeable pair of Whistling Kites was undisputable and they were immediately accepted on the list while a photo turned out to be an unmistakable Little Eagle pale morph.

Little Eagle pale morph. Photographer: Stephen Garth
Little Eagle pale morph. Photographer: Stephen Garth

Another discussion needed a scope to resolve the waterbirds on a distant dam.

Grey Shrike--thrush. Photographer: Marilyn Ellis
Grey Shrike–thrush. Photographer: Marilyn Ellis

They included a Yellow-billed Spoonbill a female Australasian Darter, a pair of Black Swans and another of Masked Lapwings plus a pair of Australasian Shovelers – and a small flock of Freckled Ducks. Weebill, White-throated Treecreeper and Australian Ravens were also heard and our final species list totalled 59.

White-throated Treecreeper. Photographer: Kathy Zonnevylle
White-throated Treecreeper. Photographer: Kathy Zonnevylle

Several people were smiling over their ‘lifers’ and the rest were grinning because we’d seen certain species for the first time for a long while. Our thanks went to John for introducing some and reminding others of Three Chain Road’s riches.

Contributor: Diane Tweeddale, Coordinator BirdLife Melbourne Weekdays Outings

Does nest box design mitigate cavity loss?

Masters student, Eliza Larson tells us what she has found

The continued decline of tree cavities is increasing pressure on many hollow-utilising species. In Australia alone, around 300 species of birds, bats and arboreal marsupials which utilise tree cavities are potentially at risk. Artificial nest boxes are commonly used to mitigate cavity loss, however they are poorly insulated in comparison. The predicted continued increases in average temperature and extreme weather events such as heat waves, makes it critical to understand how species in nest boxes may be affected by these changes, and how these effects may be mitigated.

Crimson Rosella (P.e. elegans)
Crimson Rosella (P.e. elegans)

To investigate this, I selected the iconic Crimson Rosella (Platycercus elegans) as my study species. Like almost all parrot species it is an obligate cavity breeder. In addition, there are several subspecies occupying a range of habitats and climatic zones in eastern and south-eastern Australia. It also willingly breeds in the over 700 nest boxes our research group has established. I deployed temperature loggers in each nest box, and compared temperature to nest box selection, nestling growth and survival.

Thermal image showing heat lost by two nestlings
Thermal image showing heat lost by two nestlings

I began this as my Honours project at field sites at Bellbrae and Steiglitz near Geelong with the Crimson subspecies P. e. elegans, which revealed that more extreme low temperatures were most detrimental for nestling growth, and greater temperature variability had a tendency to reduce fledging success. I was lucky enough to continue my project for my Masters, and spent four wonderful (and exhausting) months in the beautiful Adelaide Hills and Fleurieu Peninsula in South Australia. These areas are home to the orange/yellow Adelaide (P. e. adelaidae) and Fleurieu (P. e. fleurieuensis) subspecies which experience a warmer and drier climate than the Crimson subspecies in southern Victoria. In addition to nest box temperature, I also recorded characteristics such as the amount of tree canopy cover and depth of nest box substrate.

Adelaide Rosella (p.e. adelaide) brooding her newly hatched chicks under her tail
Adelaide Rosella (p.e. adelaide) brooding her newly hatched chicks under her tail

Due to relatively recent logging in the 1970s, cavity bearing trees are rare at our Adelaide Hills site. Nest box uptake is therefore extremely high, and 54 out of our 60 nest boxes had at least one breeding attempt. With the assistance of Honours student Sarah Micallef, and a few enthusiastic volunteers, we scaled ladders to monitor each four metre high nest box every two days. Our efforts were rewarded with 173 rosella nestlings weighed weekly from a total of 75 breeding attempts (32 successful, 43 failed – mainly due to predation).

Galah nestlings in a nest box
Galah nestlings in a nest box

I analysed nest box preference by order of uptake using temperature variables from two weeks prior to breeding. Nest boxes with lower average temperatures and greater temperature variability were occupied earlier in the season. No tree characteristics appeared to influence nest box preference, however nest boxes with lower substrate depth also seemed to be preferred. Although no significant relationships were found between my temperature variables and clutch size or hatching success, greater average and more extreme high temperatures had strong relationships with nestling growth rates and fledging success. For every 1°C increase in average temperature, nestlings were on average two grams lighter and around two fewer chicks were expected to fledge, while a 1°C increase in high temperatures increased nestling mass by two grams and the number of fledglings by almost one. Although the finding of higher extremes being beneficial to nestlings was surprising, it is possible that they benefit from short periods of greater temperature in the form of reduced thermoregulatory costs, allowing greater energy allocation to growth and therefore survival.

A sub-adult Adelaide Rosella with her newly hatched chicks
A sub-adult Adelaide Rosella with her newly hatched chicks

I also conducted a small study testing the effects of different kinds of insulation on the internal temperature of empty nest boxes. I applied 3cm thick polystyrene, pleated foil batts, and reflective paint to the top and east sides (where solar exposure is greatest) of nine pairs of nest boxes over six weeks. My analysis thus far indicates that polystyrene and foil batts were most effective, with both reducing temperatures during the hottest part of the day by 0.5°C on average (but by up to 6 degrees), while remaining slightly warmer than untreated boxes during the night. Reflective paint appears to be quite ineffective, actually increasing internal temperature for a short period in the late afternoon.

Reflective paint study
Reflective paint study
Polystyrene study
Polystyrene study
Foil batt insulation study
Foil batt insulation study

My findings suggest that breeding rosellas may be sufficiently flexible to cope with changing climates, but only if cavities with various microclimate profiles are available. Increased nest box insulation could be beneficial to rosella nestling growth and survival by reducing average temperatures during the day, and potentially partially mitigating the effects of heat waves and cold spells. Future work should focus on testing this in the field, and I encourage those of you who make nest boxes for your gardens to run your own experiments with various thicknesses of wood!

I am extremely grateful to BirdLife for their continued support in the form of the Stuart Leslie Research and Conference Awards which assisted with fieldwork costs and helped me attend the IOC in Tokyo last year.

Eliza Larson with an adult Adelaide Rosella. Photograph by Sarah Micallef
Eliza Larson with an adult Adelaide Rosella. Photograph by Sarah Micallef

Werribee Waders

BirdLife Melbourne Werribee Waders identification course, which was led by John Barkla, ran prior to BirdLife Australia’s Farewell the Shorebirds event.

Many of those who attended were relatively new to birding or shorebird identification, whilst some need a refresher course. With his extensive knowledge of shorebirds and beautiful photos John was able to convince participants that they would be able to identify 99% of the migratory shorebirds that visit Werribee (i.e. three species, Red-necked Stint, Sharp-tailed Sandpiper and Curlew Sandpiper) despite making us aware that individuals within a species can vary quite a lot., and that the different plumages can complicate it.

By the supper break in the middle of the evening, many were feeling a bit more confident about that.

After supper a few doubts crept in. Would they be able to pick, for example, a Pectoral Sandpiper from a Sharp-tailed Sandpiper? A sample slide gave a couple of pointers.

Sample slide. Photograph by John Barkla
Sample slide. Photograph by John Barkla

Most people left the presentation having enjoyed it, and looking forward to putting it into practice at the Werribee Treatment Plant (WTP).

Vehicles in convoy at the WTP. Photograph by Deb Oliver
Vehicles in convoy at the WTP. Photograph by Deb Oliver

We were lucky to have an almost perfect autumn day for the outing and were also lucky in that there were a couple of Pectoral Sandpipers in the same pond as Sharp-tailed Sandpipers which gave us the opportunity to compare them.

At the WTP. Photograph by Bill Ramsay
At the WTP. Photograph by Bill Ramsay

We didn’t manage to find any other of the less common shorebirds, apart from one Bar-tailed Godwit, but John gave an impromptu lesson on Tern identification as we looked out onto rocks where several species were perched at almost high tide.

Photography by Bill Ramsay
Photograph by Bill Ramsay

Even at lunch most eyes were still on the watch for birds, even if the scopes were deserted!

We finished the day with 95 species seen and a lot of tired but happy birders feeling more confident that they can identify our three most common migratory shorebirds.