Wildlife Rescue & Information Network Inc.

Nobody can deny that plastic is one of the most useful materials ever developed. It is used for all sorts of things, from wrapping food to making automotive components. Unfortunately plastic has two major disadvantages; it comes from a non-renewable resource, ie petroleum, and it is basically non-biodegradable. An item from the Journal of the Natural Heritage Trust reports that Australians use about 6.9 billion plastic bags annually, enough to stretch around the world 37 times if tied together. Unfortunately up to 80 million of these bags end up as litter – in our streets, parks and waterways. Plastic bags can take years to break down after use and, because they are so lightweight, they easily blow out of rubbish bins and travel large distances. It is estimated that more than 100,000 animals and birds die every year as a result of plastic bag litter. One way of reducing plastic litter is to recycle your plastic bags. Another option is to take your own calico or string bag when shopping.

All authorised wildlife shelter operators in Victoria operate under the ‘Code of Practice for the Operation of Wildlife Shelters.’ Paragraph 1 of Item 3, Release Procedures, states :

‘This phase of rehabilitation process is most important and must be carefully planned. The long-term survival of the animal is dependent, in part, on the release being conducted efficiently and effectively. To this end, rehabilitation must incorporate not only the physical health and well being of the animal, but must also ensure that the necessary survival skills are present. This is particularly important for hunting animals [such as raptors] or animals with highly specialised diets. In these cases, the animals may have to be taught to hunt or weaned to an appropriate diet prior to release’.

There is little sense in raising a species using artificial food when it is then necessary to re-educate it regarding a natural diet. Trying to persuade possums raised on a luscious fruit diet that gum leaves and blossom are really better is almost impossible, it takes a very long time, is incredibly stressful and not always successful, not only for the possum but for the carer also. So much easier to start with a natural diet. Yes, at times, it may take a little effort to gather the appropriate food each night but how much more rewarding to see your tiny possum clambering amongst the gum leaves sampling the small fresh leaf, then the larger older leaf and deciding which one it prefers, perhaps with a little bit of bark chewing between leaf courses. And how much quicker they learn to easily negotiate the canopy of leaves placed in their enclosure. Birds should also be fed natural, or as close to natural food, as possible. Yummy chicken or beef strips are an easy choice for the carer but these tasty nibbles are not available in the wild.

Unlike leaves and blossom, insects and other live food taken by birds do not sit and wait for capture, it is up to the bird [predator] to recognise its natural food and have the ability to track and capture it. The large hunting raptors who chase live prey must be in top condition in order to survive in the wild. Every attempt to capture prey is not successful. Each attempt weakens the bird making it a little more difficult at the next attempt. Death from starvation is usually the result of birds released without the capability of recognising and being able to capture food. For example a Peregrine Falcon, on average, will make 11 attempts before making a successful strike, each attempt ends with the bird just a little weaker until it is incapable of chasing down prey. We all know peregrines are the fastest flying birds in the world, clocking an amazing 300km+ per hr. That speed is when the bird is flying in a ‘stoop’ that is, in a downwards vertical dive with wings either fully closed or only partially open. A pair of peregrines will often hunt together, one bird will fly high with its mate much lower, when prey has been found and the chase begins, the higher bird will chase from above, the unsuspecting prey will then be caught by the low flying falcon. When flying in a stoop a peregrine may capture prey in its talons and take it to a perch to kill or hit it hard in flight either stunning or causing instant death. It then follows it to the ground to gather and take to a perch for eating. In a typical horizontal flight, peregrines find it much more difficult to capture prey. Fast flying birds, for instance racing pigeons, will almost always beat a peregrine in a horizontal chase. Goshawks are ‘sprinters’ often running down prey very quickly although long chases do occur, they will often chase their prey into the tops of trees following them into and through the leaf canopy.

The following information has been taken from a study done in 2006 by Peter H. Holz, BVSc, DVSc, Dipl ACZM Richard Naisbitt and Peter Mansell, BVSc, PhD, MACVSc. It is a summary only.

The study examined the effect of 2 fitness programmes on post release survival and ability to maintain weight of Peregrine Falcons [15] and Brown Goshawks [12] that had been captive either for treatment or after orphaning. Each bird was either treated or allowed to mature. Two exercise methods were used – traditional falconry methods or by stimulated flight within its cage. Resting blood lactate concentrations were taken and measured at various stages prior to release. [I have not noted the results of the blood tests but concentrations were higher in the cage exercised peregrines compared to those exercised by the traditional methods and there was no difference between the 2 groups of goshawks. After exercise the levels were significantly higher for the cage exercised group of both species]. Prior to release all birds were fitted with radio transmitters and monitored then trapped at various times after release and weighed.

Of the falconry trained birds 3 of 6 peregrines and all 4 goshawks gained weight. All 9 peregrines and 6 of the 8 goshawks from the cage group lost weight after release. Results would suggest peregrines and goshawks exercised using traditional methods were more fit than the cage exercised birds and would be more likely to survive after release.

The birds were individually assigned to one of the 2 groups, sex or time in captivity was not taken into account when the selections were made. The group 1 birds [6 peregrines and 4 goshawks were exercised by standard falconry techniques, initially flown 50m twice a day using a creance [training line] and food based motivation. They were then free flown twice a day for 50m until judged ready for release. Group 2 birds [9 peregrines and 8 goshawks] were kept in aviaries and fed, they were exercised once or twice a week by stimulating 10-18 flights back and forth in a 25m flight cage. They were assessed as being ready for release when handlers considered normal flight ability had been reached. Prior to release they were forced to fly 18 repetitions of an 8m horizontal flight during a period of approx. 5mins.

Birds were tracked and recaptured at variable times after release and weighed. One peregrine and 4 goshawks from group 2 that had lost weight were taken back into captivity. Exercise was then done using traditional methods prior to the second release. Where body weight remained steady or increased birds were re-released without radio transmitters.

RESULTS

Three group 1 peregrines gained weight after release, 2 lost weight and 1 could not be recaptured. All group 2 peregrines lost weight [loss range 4%-32%]. Four of the group 2 peregrines were found dead; one struck by a car. Necropsies on the other 3 found nothing significant other than emaciation.

All 4 group 1 goshawks gained weight after release. Three were recaptured a second time at 15, 6 and 2 months after initial recapture, indicating their long term survival. All 3 birds were in good condition. Six group 2 goshawks lost weight [loss range 9%-37%] and 1 group 2 goshawk died, necropsy showed nothing significant other than emaciation. One group 2 goshawk gained weight and 1 could not be recaptured but was seen alive 16 days post release.

Four goshawks and 1 peregrine in group 2 that lost weight after the initial release were taken back into captivity and exercised as group 1 birds before re release. All 4 goshawks gained weight after the second release. The peregrine lost 8% of its body-weight after the second release but this was substantially less than after the first release [18% of body-weight].

Results show training prior to release using traditional methods increases the survival chances of these birds. None of the group 1 birds died and most either maintained their release weight or gained. Group 2 birds commonly lost weight, all deaths were of group 2 birds. All but 1 of the group 2 birds retrained using traditional methods gained weight after the second release.

Successes between the 2 species were different. The goshawks from group 1 when recaptured had not lost weight, 2 of 5 peregrines on recapture had.

The data suggests peregrines need a more intense training regime than the goshawks. Peregrines tend to spend more time on the wing searching for prey than do goshawks who also search while perched.

A report by Birds Australia says there is mounting evidence that climate change will have, probably already is, having an impact on our bird species. The way they breed, migrate and feed are undergoing great changes even though the measurable increase in temperature in recent decades seems minor. Experts forecast if temperatures rise between 2C and 5C more than they were in 1990 by 2070 extinctions for some species will occur following a progressive collapse of regional populations. It is thought this collapse may already be happening.

The report is a collection of papers by scientists who say tropical and subtropical seabird breeding colonies in northern Australia are in decline. In an area of the Great Barrier Reef numbers of the Brown Booby have crashed by 85% since the 1980’s. In another area the numbers of 2 Tern species have fallen by 30%. The increasing incidence of El Nino weather events is causing the problems as warmer seas reduce fish availability as well as other foods for seabirds, it is thought the food is forced into deeper water. During the 2002 El Nino event the mortality of Wedge-tailed Shearwater chicks on Heron Island was 100%. Two thousand [2000] adult birds also died.

The report identifies the birds of the savannas and rainforests of northern Australia as being among the most at risk from climate change with 55% of the 387 species recorded anticipated to suffer big population declines. In the wet tropics of north Queensland a suite of species that are confined to high altitude rainforests face extinction as temperatures rise. The Golden Bowerbird is one under particular threat. Chowchillas and Fernwrens habitat is also contracting upland at a steady rate.

It is believed the rise in temperature will cause sea levels to rise, ultimately vast areas of the wetlands of Kakadu and Gulf of Carpentaria will be covered by salt water, this will destroy the habitat of Magpie Geese and other freshwater birds. Elsewhere in the north hotter and more frequent fires will put pressure on other endangered birds such as Golden-shouldered Parrots and Gouldian Finches, an expected increase in the frequency of cyclones will impact on Cassowaries.

The warming is altering feeding behaviour and creating problems, Kookaburras are moving into higher mountain areas once too cold for them, they are feeding on Alpine Skinks who make no attempts to hide as the new arrivals are not considered a predator by the skinks. This species of skink is being wiped out.

Thirty one birds are considered to be at high risk of extinction, they include the Mallee Fowl, Orange-bellied Parrot, Albert’s Lyrebird, Hooded Plover and Fairy Tern.

The report goes on to say many birds that may have been able to adapt to climate change will be at risk because their habitat has been fragmented by land clearing. The report explains that temperature changes affect bird populations because climate regulates the geographic limits of their distribution; it sets boundaries of environmental conditions within which a species can function. Climate provides the energy and water inputs that determine rates of plant photosynthesis, growth and decomposition. Small changes in temperature may mean the habitat of a particular bird is no longer suitable for its needs. Noted climate related habitat changes in recent decades affecting bird populations include eucalypts encroaching into rain forests and woody weeds into inland woodlands; a 40% reduction in snow depth and the spread of trees into alpine meadows and glacial retreat in the sub Antarctic and Antarctic.

The report comments that all is not as gloomy as it may sound as warmer waters further south are boosting the numbers of temperate seabird species, eg. Australasian Gannet population has increased threefold in the past 2 decades in Bass Strait.

The warmer weather has led to northern bird species spreading south, Figbirds and Common Koels unknown as far south as Sydney are now seen in Victoria. Pied Butcherbirds, White-headed Pigeons and Pheasant Coucals have expanded their range south, their southward journey continues at a rate of between 100km to 150km a decade. This indicates some species have the ability to adapt. Others don’t.

Migration patterns established over thousands of years have markedly changed in a little more than a decade. White-throated Nightjars and Little Bronze-cuckoos, strict summer visitors to some areas now arrive earlier and stay later.

Breeding behaviour is changing, this is probably due to a combination of the warmer temperatures and decline in rainfall over the past 10 years. Studies of Masked Lapwings show birds are nesting 2 days earlier a year in north Queensland and one day later in southeast Australia. Breeding success of this species in Tasmania is declining by 1.5% a year.

Introduced weeds will prosper in the warmer temperatures, fire adapted weeds will accelerate the frequency and severity of fires. The Queensland government warns their extensive savanna woodlands in the north could end up as treeless plains. Invasive species are the big winners from climate change, this is not good for many birds. Increased levels of carbon dioxide are expected to reduce nitrogen levels in eucalypt leaves, reducing the populations of lerp insects. These lerp form a major portion of the diet of honeyeaters and many other bush birds.

Ed note : Over the past 10 years Garry and I have noticed a huge drop in the number of individual birds and the number of species in our region. As for the Lerp on eucalyptus trees, haven’t seen any for years, our gliders in care miss out on that treat each season.

A ‘MISTAKE OF EAGLES’

Shelter operators are sometimes stumped by the descriptions of birds or animals they receive over the phone and find it impossible to offer an identification. Similarly, when a patient arrives it can often be far removed from what has been expected and prepared for. Owls are mostly frogmouths, baby snakes are often legless lizards, baby rabbits are wombats and pinkie possums turn out to be rats! One of my most memorable was the day I received a call for a baby wedge-tailed eagle and what a bugger that was, Garry and I had just returned from transporting a juvenile Grey Goshawk and a Black Falcon to Healesville to Richard Naisbitt, Keeper-of-the-Mews, who shortly after became my mentor on anything raptorial as well as a very good friend to Garry and I. Another raptor, particularly a chick was not in my immediate plans.

Arrangements were made for the caller to bring the chick to me. About half an hour later I noticed a car driving through the second gate in our driveway – this is not on, no-one drives through that gate – I charged outside and signalled the driver to reverse back through the gate then pointed out the rather obvious sign attached to the gate to the person who had opened the gate. She then reached into the car and lifted out a feathered magpie chick sitting quietly in its nest. After her first few words I became a bit confused and asked “are you the people with the baby eagle?” Yes was the reply. I was then compelled to ask what seemed to me to be the obvious, if they knew the bird in the nest was a magpie. The response to this was the person holding the bird hit the driver on her shoulder and yelled “I told you it wasn’t an eagle” to which the driver replied, “but there’s lots of eagles nesting in that tree, they’re there all the time” [the tree was, apparently, a cypress in the front yard of their home] and with that she lifted the ‘tinny’ resting between her legs and took a long drink. I took the bird, the passenger climbed back into the car and the driver reversed down the drive and off they went leaving me more than a little in awe of how the driver had safely negotiated her way through the 2 gates going forward then managed to also reverse back to the road, but oh so thankful she had!! Mostly we try to reunite magpie young with their parents but I thought in this instance it possibly wasn’t in the best interests of the bird so settled it, still in the nest, in a suitable cage and it was eventually released with others.

The goshawk I mentioned needed flight and hunting practice prior to release [I had received him for care some time earlier as a few day old fluff ball]. The falcon had been in care for a number of weeks after being found on the ground, luckily for it the finder brought her to us immediately. She had a break to the radius, the smaller of the 2 bones that connect to bones at the wrist at one end and the elbow at the other [the same as our lower arm], hopes for her survival were not great but the radius was secured in place using those plastic fasteners used for securing garbage bags and our fingers were firmly crossed. With lots of care and good food she was finally ready to go but, being one of our rare raptor species, I wanted Richard to work with her prior to release.

What a magnificent bird the female falcon was. One of our more rare species and as angry a bird as we have ever cared for. Her food [her natural diet of other birds and mammals – dead of course] was thrown to her each morning and once or twice a week any remnants were cleaned up using a long handled plastic rake that I poked through the door, she would constantly attack the rake as it was being pushed backwards and forwards gathering the bones and feathers she left. I often commented to Garry that if he came home one day and couldn’t find me he should first look in the aviary where we kept the falcon, if my boots were in there then I hadn’t moved quickly enough and she’d dragged me through the door and had me for breakfast. I reckon 15 minutes would have been all she would have needed to reduce me to boots and bones.

I have special memories of taking those birds to Healesville, first, the weather – it was freezing; second, the trip – we got to the Macedon Ranges where the fog descended like a solid wall and within minutes we came to an abrupt halt behind a long line of stationary cars, it took a while before we found out there had been an accident. We were held up for almost 2 hours. Every 10 minutes or so I leapt out of our car – a large Toyota Hi-ace van – ran to the back door, opened it and threw myself into the back to check the birds – the people in the car behind must have thought I was crazy; and, third, after being stuck for so long in the fog panicking about the birds, I began to doubt my identification skills and wonder what Richard would think of my identification talents, as at one time I’d called him and said I thought the young Goshawk was actually a female Sparrowhawk as it was so tiny, then later called him again to say no, it’s just a very small male Goshawk.

On arrival Richard met us, gave the birds a quick look through the doors of their cages – he said he thought the ‘goshawk’ was a female sparrowhawk! Damn! He told us to go for a quick coffee while the vets checked the birds then come back to the surgery which we did. To my great joy he said the bird was a male Goshawk, but it was incredibly petite and made the comment that the Black Falcon was the first one taken to Healesville correctly identified, all others had been dark phase Brown Falcons and that was what he had been expecting. He was also pleased that only natural food had been given to both birds as he said most arrived in poor condition having been fed mince or chicken fillets. We were given a tour of the mews, visiting all raptors in care and I was privileged to be given permission to hold a fluffy rare Grass Owl chick that was being hand raised. A very long but immensely rewarding day.

And then there are the correct identifications that we have a little trouble believing :

‘CRIKEY’

Earlier this year I received a call from the WRIN phone operator to say she had received a call for a crocodile. It was on the footpath outside a particular building. The location had been given to the rescuer and he was on the way. My suggestion to the surprised operator was that it was probably a lizard.” Well, just goes to prove not all people have difficulty identifying wildlife. The rescuer called in, from a distance he was sure it was a crocodile, yes, it was definitely a crocodile. Our rescuer, apparently, approached the small specimen with care, picked it up and placed it in a box, it had a leg injury – the leg was hanging off – he also mentioned there was sawdust trickling from the ‘wound!’ I saw it later on and it sure looked real. In fact it was a mounted specimen.

This funny episode got the phone operator telling me about the call she had on New Years Eve regarding an elephant in a dam, she said she played along with the caller saying she would send a rescuer but some heavy equipment would be required to lift the elephant out of the water. I suggested perhaps it should be investigated – tongue in cheek – as some years ago I received a call about an elephant in one of our local forests, it had been seen in a garden, the caller said it had damaged a couple of fences and left several serves of fertilizer. Being summer there were a number of logical explanations to the sighting – too much sun; too much liquid refreshment, etc. There was eventually a logical answer and many apologies made to the caller whose garden had been visited. Seems there had been a circus in Dunolly, a few kms north of our place and Jenny the elephant had decided a jaunt through our local forests would be something of a change so she spent several days wondering through our bush. I’m still amazed that it took several days to refind her after the reports from all the people whose gardens she had visited. trampled and fertilized. It’s not as if a full grown elephant could hide behind a tree, at least not the trees in central Victoria, most are smaller than SEC poles! But goes to show we should never disregard calls.

The  White  Winged Chough [pronounced chuff and sometimes known as Black Jay  locally]  is  still fairly common in our area although we see them less now than we used to, perhaps they are having to enlarge their food gathering areas so take longer to complete the circuits. A  Chough is a large black bird that has a white under-wing patch that is  only visible  in  flight or when the bird is displaying. Another  feature  is  the down curved bill and the red eye of birds over 4 years old.

In over 20 years I have only received one or two young Choughs in the shelter for care. Once the bird has been checked to ensure it is healthy and not injured the only way to ensure its survival is to return it to its family or find another group and persuade them to take the young bird under their wing, so to speak. It is rare the offer of a new member for the family is rejected, the young birds are usually quickly accepted into the new group.

Choughs have a very interesting and tough life, an article published in the Australian  Nature magazine several years ago  gave us a peek into the lives of these large, gregarious birds.

Life for a Chough is particularly hard and a pair simply  cannot  breed without help. This explains why Choughs are found in groups of 4 to 20  birds during the breeding season. When not breeding more than one group of Choughs’ may come together to a regular food source. A  lot  of their food comes from beneath the ground and  therefore  the  birds spend  a lot of time digging holes, some up to 20cm deep. Digging uses a  lot of  time and energy and old birds learn that digging around grass tussocks  is more  likely  to  yield  a  beetle larvae  or  something  else  edible.  More importantly,  mature  birds learn when to give up digging in  an  unproductive patch whereas young birds will continue to dig and end up with nothing for all the energy expended. Choughs are interesting to watch as they search for food on the forest  floor, often they are so engrossed in their search that they don’t notice an observer and  will  carry on tossing leaf litter from side to side in search  of  their elusive meal.

Choughs  build a large bowl shaped mud nest approximately 35cm  across.  Four eggs that take 3 weeks to hatch are laid by the breeding pair, the young  then take  4  weeks to fledge; young are fed for up to 8 months.  Many  songbirds  only  look after their young for twice the  nesting  period  but Choughs  continue  their support for up to 8 times the  nesting  period.  The young  must  have  this  support  until  they  master  their  basic   survival techniques. The  time and experience needed to find food means that one pair alone  cannot supply  all that is required to feed a clutch of young.

Of the  few  recorded attempts  by  single pairs of Choughs to nest they have lost  their  young  to starvation. The minimum viable group size is 4 and even so these 4 will  only raise  one  chick. Each additional helper increases the chances of  a  chicks survival to where a group of 10+ can occasionally raise all 4 chicks.

The offspring from previous years help in all instances from building the nest through to caring for the fledglings.

Neighbouring  groups  of  birds  will sometimes  destroy  each  others  nests, intruders peck at the foundations of the nest in an attempt to dislodge it, if this is unsuccessful they will destroy the eggs.

If  the  nest  is destroyed it often stops a group from  breeding  again  that season  as the mud needed to rebuild may not be available at the time.  These delaying  tactics reduce the competition for food from groups close by  giving the intruders young a better chance of survival.

Kidnapping also occurs amongst Choughs with large groups ganging up on smaller groups. Some birds from a large group will engage members of a smaller  group in  battle  whilst others approach a juvenile and attempt to entice  it  away using  a tail-wave and wing-wave maneouvre. If the enticement  is  successful the  young bird is fed immediately and within a short period it acts as if  it has  always been with the group. Young Choughs appear to be  easily  confused and  perhaps have not developed a bonding with their group so early in  life. Kidnapping  doesn’t  occur later than a month or so after  fledging  when  the birds have more than likely bonded to their home group. A  group  of birds willing to feed someone elses offspring for 7  months  must surely be an indication just how desperate a group is to gain another  helper. Does this show how hard life is for a Chough?

DNA  fingerprinting has found that when the structure of  a  group  of Choughs is stable one pair dominates the reproduction year after year but when deaths  in  the  family  have fragmented  groups,  helpers  try  out  different combinations  with others that they meet in their travels until they work  out who is likely to produce the best offspring.

Chough groups are highly inbred, often the breeding pairs are closely related. Disasters such as droughts that cause members of groups to die may well be the way new blood is brought into family groups.

Chough's Mud Nest