January 12th 2005
The Cry of the Curlew
Perhaps, more than any other impression, the strange and shrill cry of the curlew is the most distinctive of Magnetic Island. Now, with the permission of author and wildlife carer Tania Scheutt and artist Robyn Schae, Magnetic Times is delighted to reproduce "The Cry of the Curlew": their very informative brouchure on this iconic Island bird.
The haunting, eerie, mournful sounds heard at night on Magnetic Island are the cries of the Bush Stone-curlew. Stone-curlews belong to family Burhinidae represented throughout the world by nine species in two genera. Two species are found in Australia, one from each genus: the Bush Stone-curlew (Burhinus grallarius) and the Beach Stone-curlew (Esacus neclectus).
The Bush Stone-curlew, also known as Bush Thick-knee, Southern Stone-curlew, Southern Stone-plover, Weeloo, Willaroo, Angelbird and Scrub curlew, was once found across much of Australia, except for very arid regions and heavily forested areas. It is now rare to totally extinct in closely settled parts of Australia and dwindling in numbers elsewhere. In some states it is listed as vulnerable or threatened.
Ground-feeding, ground-nesting woodland birds that are larger than 500 grams are the bird species most endangered in Australia and the Bush Stone-curlew fits every one of these criteria. This bird is the emblem of Moorabool Shire in Victoria because Moorabool is local Aboriginal for 'the place of the curlew' or 'the voice of the curlew'. But for the last 50 years curlews have not been seen there.
Bush Stone-curlews are nocturnal, cryptic and very well camouflaged. They are fairly large ground-feeding, ground-nesting woodland birds. Adult total length is 55-60cm, wingspan 80-105cm and weight 550-750 grams. They stand at around 50cm and when sitting down are about 30cm high. The dark grey bill is 5-6 cm long, thick and straight. Curlews have large yellow eyes, a long neck, camouflaged grey-brown upper parts with bold black streaks and cream under parts. Their long legs are thin and delicate with thick knees which they fold backwards when sitting. Their three front toes show traces of webbing but there is no hind toe.
Ecologically they behave like woodland birds while technically they are classified as waders and therefore possibly do not breed until they are 2-3 years old. There is no known way of sexing Bush Stone-curlews externally; so far a blood test is the safest and most reliable method.
Magnetic's most distinctive creature
Curlew presence is most often indicated by their wailing calls after dusk. They are most active from dusk to early morning and are particularly active on moonlit nights. Their eerie cry is persistent during mating and nesting time or when rain is about. Those wailing, screaming, haunting cries signify disturbance, danger, communication, territorial disputes or the loss of an offspring or partner.
Curlews can fight fiercely for various reasons, pinning the opponent to the ground, attacking it on the neck, the back, between the wings, or grabbing it by the tail and swirling it around. At times they kneecap their opponent.
They fly only when frightened or to gain better feeding ground or to socialise. They are shy and watchful, moving slowly with their heads outstretched. They run a short distance, stop, peer and flick their tails then repeat the process again and again. Their resting positions are standing on one leg, sitting or lying stretched flat.
On Magnetic Island the behaviour pattern of Bush Stone-curlews has changed dramatically in recent years. Lowland areas are mostly residential and development is taking over their habitats with greater activity and disturbance from humans and domestic animals. Consequently they now depend on friendly property owners, residents and visitors.
During the day curlews normally shelter on the ground in lightly timbered habitats among fallen tree debris where their mottled plumage forms camouflage and the open terrain offers good visibility. They need this type of habitat with sparse grass cover and abundant fallen tree litter for feeding and roosting. Curlews are usually not found in grasses higher than themselves. Some native grasses do grow tall but not densely and this allows the birds to see predators. Curlews mainly inhabit lowland open forest, woodland and sandy creek beds but they are also seen on golf courses, in parks and many other locations.
Curlews eat a variety of foods such as crustaceans, grasshoppers, spiders, lizards, centipedes, snails, small frogs, small reptiles, ground beetles, crickets, caterpillars, seeds and small fruits. They eat only what is on the surface and do not scratch for food.
Magnetic Island curlews breed between July and February. Breeding birds strongly defend their territory but at other times of the year they are non-territorial. Nests are consistently located in relatively open areas on bare ground, often surrounded by a few sticks, leaves and small stones. This enables the sitting bird to achieve good ground vision in all directions. The same nesting sites are re-used in successive years but nests may be abandoned if surrounding grass becomes too tall or disturbance is too severe.
Curlews usually lay two eggs directly on the ground. These are mottled grey-brown the size of hen eggs. They are laid 24-48 hours apart and incubation begins with the laying of the last egg. Occasionally two females lay their eggs together, making a nest of 3 or 4 eggs. Parents take turns in sitting, with the off-duty bird usually standing guard nearby. Incubation takes 22-28 days. Parents can hear chirps through the eggshells and they make soft clucking noises to the chicks.
Curlew chicks can walk almost as soon as they hatch; and when the parents eat the tell-tale eggshells as a calcium supplement, the chicks are led away from the nest to a more protected area. Newly hatched curlew chicks weigh 26-34 grams and are covered with thick pale grey down and are boldly marked with dark brown to black stripes.
Parents communicate with their young by making low clucking noises. Sometimes dissecting food, they then pass it directly to the chicks by dropping it in front of them, clucking and stepping back. This continues until the young are almost fully grown, except when breeding begins again, often when chicks are only 3 weeks old. Pairs behave in different ways in these situations: some allow their young to remain, feeding them until the new clutch hatches; others viciously chase them away, forcing them to try to fend for themselves.
Two clutches are common and even 4 clutches may be produced in the same season, usually after the loss of very young chicks. It is common to abduct or adopt offspring from other pairs and raise them with their own. The last brood remains with the parents until breeding begins in the next season.
Curlews are sedentary and can live to 30 years. Most pairs stay together in the same territory throughout life. Young curlews may be unable to establish territories because all of the available habitat is already taken by adult pairs. This is particularly apparent on Magnetic island where pockets of 20 or more birds can be found throughout the year.
Predators and other Dangers
On the mainland major threats are foxes, feral cats and dogs and roaming domestic animals. More wildlife is harmed near rubbish tips than elsewhere because of the populations of feral animals there. Only goannas and some large snakes are known natural predators of adult curlews, while young curlews also fall victim to hawks, kites, eagles, kookaburras, owls, crows, currawongs and other carnivores. When approached, all curlews, even the newly hatched, either run or freeze - lying flat on the ground, head and neck outstretched, relying on camouflage for protection. Therefore it is truly difficult to see camouflaged eggs, chicks or breeding adults and at times they are accidentally killed by lawnmowers or slashers. As young curlews cannot fly until they are about 50 days old, they are vulnerable and most parents distract potential threats with dramatic displays. Adults will also hiss, grunt and growl loudly with wings outstretched, tail fanned and erect or they will run from the threat.
Most road-kills occur at dawn and dusk, in overcast conditions and during or after rain. Curlews, including the young, frequently run onto the road and under streetlights to pick up insects or sit on the warm bitumen.
On Magnetic Island curlew numbers are rapidly declining due to habitat loss and fragmentation, road-kills, disturbance from domestic animals, both natural and feral predators and food shortages. There are so many odds against them.
With some consideration, we can save these strange birds that fascinate almost every person who stays a night on Magnetic Island and hears the cry of the curlew.
Researched, written and published by Tania Schuett, Magnetic Island native bird carer since 1980.