2009 Question of the Month inquiries

Insect screens are a great way to cut down reflectivity, without altering your windows.

Silhouettes or decals reduce the probability of collision by interrupting the expanse of glass.

Answer:

Birds and Windows

This Musk Lorikeet (Glossopsitta concinna) died after hitting a window in Yangan outside Warwick. Musk Lorikeets form large flocks, which forage in the outer canopy of flowering and fruiting eucalypt trees. When alarmed, Lorikeets swoop down from trees and fly off fast and direct. This is when they are in danger of striking windows.

Birds may not see glass as a barrier in their flight path. Large windows can appear as either a mirror image of surrounding habitat or a continuing corridor to the environment on the other side. It has been shown that birds will hit windows regardless of the size, height from the ground or orientation of the window. Window strikes occur in any environment where birds and glass occur together.

Head trauma is the most common cause of death. Survivors that do not immediately fly away are likely to be concussed. These birds will often remain fairly motionless, breathing heavily, and after a while either succumb to their injuries or recover.

If you find a bird in this condition you can place it in a protected warm enclosure, with some food and water. Try not to touch or check on the bird too often. If the bird is still stunned after several hours, it may have more serious injuries and you should contact your local vet or wildlife care group.

So what can I do?

Does this mean that all windows are a threat to birds? Theoretically yes, but large un-interrupted expanses of glass are most dangerous.

Luckily there are techniques to make glass "visible" to birds. The main way to do this is to create "visual noise". This is a visible differentiation of material, texture, colour or opacity that helps to fragment window reflections and reduce overall transparency. The key is to cover the expanse of window so that birds are not presented with large areas of clear glass.

Visual noise can be created using vertical blinds or shades with wide slats, hanging heavily patterned, bright curtains close to your windows, or adding ornaments (e.g. decals, silhouettes) or artwork to your glass exterior.

Moving feeders and bird baths to viewable locations but away from windows may also help. Overseas studies have shown that suburban environments where birds have access to resources such as feeders, bird baths and fruiting or flowering trees encourage higher densities near homes, leading to more collisions.

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Four bony plates are fused together to form the 'plastron' or underbelly.

A nesting Green Sea Turtle (Chelonia mydas).

Answer:

No it's not a tree branch, or a tooth. It's a turtle belly bone!

The mysterious object is part of the underside or plastron of a sea turtle skeleton. The underside of sea turtles is protected by the plastron, a bony scaffold to which the shell is attached. This particular bone is called the hypoplastron. This bone is one of four similar ones, fused in pairs, which together form the plastron.

Interestingly, the plastron incorporates special bones called belly ribs, or gastralia. Belly ribs are found in the skeletons of many reptiles, including dinosaurs. In other reptiles, belly ribs reinforce the underside of the animal, acting as a girdle to hold in the guts. In turtles they have been fused and expanded to help form its armour.

The species of turtle can be determined from just this one bone. This bone is from a Green Sea Turtle Chelonia mydas which would have been approximately 30-50 years old when it died.

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The mangy fox runs for cover.

Fox with normal bushy tail.
Photo: Queensland Museum

Answer:

An inquirer from Mt Tamborine, Queensland reported an unusual predator after hearing a commotion amongst the chickens in her garden one morning. She 'captured' the culprit on her camera.

The chicken-chaser is a Red Fox, Vulpes vulpes that is suffering from severe Sarcoptic mange.

Sarcoptic mange is caused by a tiny mite, Sarcoptes scabiei. These mites burrow in the surface of the skin. Severe cases result in shedding of fur and are often associated with infections that can leave the skin leathery and corrugated.

Animals suffering this condition have been variously reported as Thylacines (believed to be extinct), dog/cat hybrids, leopards and pumas. Foxes suffering from severe mange are probably responsible for the bulk of Queensland "Thylacine" sightings.

Sarcoptes scabiei, the mite species that causes Sarcoptic mange in animals, is a species that originally infested humans but has now "spilled over" to many species of domestic and wild populations throughout the world. Apart from foxes, animals that sometimes suffer severe Sarcoptic mange include wombats, dingos and dogs. Mange can also be caused by other species of mites.

Foxes are a declared class 2 pest animal in Queensland and pose a serious threat to native wildlife and livestock. Foxes have been implicated in the extinction and decline of many native species within Australia.

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Red-triangle slug feeding tracks.

Snug slug shelter.
Photo: Queensland Museum

Golden and bright red forms of the Red-triangle Slug from the Border Ranges region.
Photo: Queensland Museum

Answer:

Karen Haggitt from Northgate phoned the Inquiry Centre about large slugs that were grazing on her garden table one wet afternoon. These are Red-triangle Slugs, Triboniophorus graeffei. These large (70mm) native slugs are common in the Brisbane region but seldom seen as they are usually nocturnal and secretive.

They are easily recognised by the red triangle surrounding the breathing pore on their backs.

They are not pests. Unlike the many species of introduced exotic slugs that eat plants, Red-triangle Slugs feed on the algae and lichen attached to tree-trunks, rocks, garden furniture and concrete paths.

Usually the only evidence of their presence is the feeding tracks they leave behind (see picture kindly supplied by John of Ocean View). Overcast rainy days and the luxurious growth of algae and lichen have brought them out of their hiding places in many areas of Brisbane.

In some areas these slugs may be bright pink, red, gold or orange. Scientists have yet to determine whether these are simply colour forms or separate species.

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Camponotus intrepidus.

Answer:

Over 200 species of birds are known to treat their feathers with the defensive secretions of ants. This distinctive set of behaviours is known as anting. It is not known why birds do this. Likely reasons are for feather maintenance and comfort. It is possibly relevant that the acidic ant secretions are insecticidal so anting behaviour may reduce loads of ectoparasites. It may also assist in the removal of stale oils in the feathers.

The ants being used by the bowerbirds were particularly large and possessed powerful jaws. A specimen was carefully collected and sent to the Inquiry Centre for identification.

The ants are a sugar ant, Camponotus intrepidus. These large ants are usually nocturnal and live in large subterranean nests. The reason the bowerbirds could access large numbers of them during the day was almost certainly because the ants were "swarming", with many winged ants emerging.

Some published accounts of this behaviour in Australian birds include the following articles from the journal Emu:

• Chisholm, A.H. (1960). Further notes on anting*. Emu 60, 131-134.
• Chambers, AP and Chambers, GK (1981). Anting by Golden Bowerbird Prionodura newtoniana*. Emu 81, 112-113.

Staff from the Inquiry Centre recently collected a live nest of this species of ant. This colony is now on display at the Inquiry Centre.

* The content found by using these links is not created, controlled or approved by this department. No responsibility is taken for the consequences of viewing content on these sites. These links will load into a new window.

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Answer:
Investigating further, there are no outer shells so they're not eggs.

And each pellet was found to be comprised of plant fibre, so it wasn't from a spider either.

In fact, the whole series of beads is enclosed by a tube of thin tissue.

This is the lower intestine of a plant-feeding mammal, almost certainly a ringtail possum. An unknown predator has eaten a ringtail and then decorated the house guttering with this "gutter" from the unfortunate possum. While many predators may relish the bones, gristle and meat of their prey, they often shun the intestine.

A bird of prey is the suspected house decorator. A few different day-active birds of prey might leave an uneaten intestine but there is one species in particular that is suspected above all others… Crows are well-known for raiding ringtail possum nests during the daytime.

This macabre souvenir was kindly donated by its finders and will be displayed in the Inquiry Centre drawers.

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Female Bearded Dragon tending her nest.

Answer:
Our original response was "Bearded Dragon eggs could take anywhere from 50 to 70 days to hatch - depending on temperature". Subsequent events have proven us wrong!

The laying of a clutch of Bearded Dragon eggs was observed and photographed by Melanie Tasker and her family on the 28th of November, 2008. The Taskers were equally fortunate to observe the hatching of these eggs on the 11th of March, 2009. This is a recorded natural incubation period of 103 days, substantially longer than incubation periods normally reported for artificially incubated clutches. Perhaps the nest was in a location that experienced fairly cool soil temperatures during the incubation period.

Thank-you to the Tasker family for a great series of photographs.

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Answer:
Thanks for the interesting photos!

Brown kookaburra from Tingalpa.

We have had reports of all black or dark brown Laughing Kookaburras recently from Nanango and Tingalpa, Brisbane. At Tingalpa there is a dark brown and a black kookaburra in the same group. Since kookaburras live in extended family groups these birds are probably close relatives.

Black or dark brown feather colour in birds is due to melanin, and excess production of dark pigmentation is called melanism. Many bird species are known to occasionally produce individuals with extra black pigmentation, including Blue-winged Kookaburras, Laughing Kookaburras, egrets, owls, penguins, partridges and pheasants.

Melanism is usually caused by a genetic change and the genes responsible for melanism in birds are fairly well understood. Very simple genetic changes, sometimes even a single mutation, can produce radical changes in melanistic colouration.

Are we witnessing evolution in action? Will legions of future kookaburras look like they're barracking for the All Blacks?

Probably not.

We are, however, being treated to a dramatic first-hand glimpse of the raw material used in evolution - variation. This variation probably won't enhance these kookaburras' breeding success so their genes probably won't increase in frequency in future generations. But under some circumstances melanism will help birds: it can make feathers tougher; it increases the warmth they receive from the sun; it affects how visible they are to other animals; and it is thought that it can indirectly enhance their immune system.

If you want to view other reports of black kookaburras or would like to post your own sightings visit the Birds in Backyards Forum on black kookaburras*.

* The content found by using this link is not created, controlled or approved by this department. No responsibility is taken for the consequences of viewing content on this site. This link will load into a new window.

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