Sunday, 28 December 2014

Whiskered Terns on the Gippsland Lakes

Whiskered Terns are a nomadic inland water bird species that prefer shallow freshwater wetlands. They turn up on the Gippsland Lakes and associated wetlands after being absent for many years.
Whiskered Tern in breeding condition with red bill and legs, black cap and dark grey underparts.
The Gippsland Lakes, located adjacent to the Ninety Mile Beach in East Gippsland, are the largest inland waterway in Australia. Not surprisingly they provide important habitat for many species of water birds including international migrant and resident species. The whole of the Lakes system is declared a Ramsar Wetland and an IBA (Important Bird and Biodiversity Area).
For more information regarding Ramsar and IBA’s see:
Given the extreme boom/bust wet/dry cycles which impact arid inland Australia it is not surprising to find that many of our resident bird species populations also boom and bust and as a survival strategy many species are nomadic, moving long distances in response to push pull factors to find suitable habitat.
Many water bird species such as ducks, ibis, herons, egrets, stilts, grebes, terns, pelicans, plovers and cormorants can flock to inland waterways and breed up in huge numbers when conditions are good. However when the inevitable drought sets in these same birds must move towards the coast to find refuge. The Gippsland Lakes are one such important coastal wetland refuge.
Back in November 2013 I found a large number of Whiskered Terns feeding over dry sheep paddocks near Hollands Landing and reported on these in a blog post. Background information about this species can be found here:
Whiskered Terns are still around the Lakes and one year later in November 2014, I encountered a flock of about 100 birds at the SE end of Raymond Island. The birds were resting on a small timber jetty along with some other water bird species. By slowly approaching the jetty I was able to get close enough to capture some photos of the activity on this small jetty.
Two White-faced Herons sharing a jetty with Whiskered Terns.
A pair of Masked Lapwings were also on the jetty.
Note the whitewash – the lack of toilet training is a great source of annoyance for humans who after all build the jetties for their own use and no doubt would be happy to share the facilities with the birds if only they did not coat them with liberal quantities of guano.This issue aside man made structures around the Lakes provide important roosting and resting and sometimes nesting habitat for water birds.
All lined up facing the same way – always into the wind.
Whiskered Terns were constantly leaving the jetty and returning in the brisk wind conditions - flight was easy for these masters of the air.
A free post top with only room for one.
The Heron has had enough of the photographer edging out along the jetty and perhaps the melee of Terns coming and going – time to find a more peaceful resting place.
Two uncommon Common Terns were among the Whiskered Terns.
Often a large flock of terns, say Crested or Whiskered, will contain another species, in this case a pair of Common Terns. This Tern species derives its name from the northern hemisphere where it is very common however it is uncommon in Australia where small numbers visit between October and March.
When I spotted this plastic snake its purpose was immediately apparent.
I have seen many attempts to scare birds off jetties (and boats) using fake raptors and owls for example, however this is the first time I have seen a plastic snake used.
I think based on the evidence of this photo the snake is a failure.
Here are a few more shots of these beautiful birds.

Eventually when the drought in the NSW Murray Darling basin ends these birds will no doubt disappear from the Lakes – it is good to know that they have found refuge here.

Friday, 26 December 2014

Mistletoe and Mistletoebirds – a fascinating relationship

The text for this post was prepared for an article in BirdLife East Gippsland’s newsletter, The Chat, Number 62 December 2014.  Some of the photos and captions have changed.
Mistletoe is a name applied to parasitic plants that grow on other plants and derive water and nutrients from their host. Mistletoe is widespread throughout the world including Australia where there are numerous species adapted to growing on many species of host plants. Willis et al in their Field Guide to the Flowering Plants of Victoria state there are 12 species of mistletoe in Victoria with Drooping Mistletoe (Amyema pendula) (Loranthaceae) probably the most common species. Jean Galbraith in her field guide, Wild Flowers of South-East Australia, lists some 21 species for a larger area. There will be many more species for Australia.
Mistletoe are seen by some as pest plants as heavy infestations may kill the host tree, usually when it is weakened by disease or drought. However mistletoes are important plants as they add greatly to biodiversity, providing significant quantities of high quality food. Also their dense foliage provides excellent roosting and nesting opportunities. 240 bird species have been recorded nesting in mistletoe, some 75% of Australia’s resident bird species.
The Mistletoebird, a species of flowerpecker, is native to Australia, where it is widespread, and some of the islands to our immediate north, though it is absent from Tasmania. As the name implies, the Mistletoebird has a close association with mistletoe plants and in Australia is probably the main species responsible for the spread and on going survival of mistletoe. While Mistletoebirds do eat the nectar and fruits of other plant species, and also insects and spiders, their diet is heavily concentrated on the fruits of mistletoe and their digestive system is specifically adapted to this specialised diet.
The mistletoe fruits can pass through the Mistletoebird’s digestive system and be expelled within 4 to 25 minutes. The fruits are ejected with little change and the sticky surface allows the seed to stick to the bark of plants where it has a chance of taking hold. The Mistletoebird actually wipes the seeds onto the branches of plants as they are excreted, thus promoting the spread of their principle food source.  
Male Mistletoebird - they are brightly coloured but hard to see and most often detected by their call.
The more sombre coloured female Mistletoebird.
The specialised diet of mistletoe berries and the adaption of the Mistletoebird’s digestive system to this diet starts very soon after the young birds hatch. Apparently the young birds are first fed on insects, however mistletoe berries soon become a prominent part of the young bird’s diet.
The following sequence of photos, starting with the beautiful nest, show the young being fed mistletoe berries and the associated waste management process.
Mistletoebird nest in Snowy Daisy-bush.
The female Mistletoebird builds the nest with no help from the male. She lays between three and four eggs and incubates the eggs herself. After the eggs hatch both parents feed the young.
The Morecombe field guide nest section (p416) describes the nest as follows, “The suspended nest is tiny, neat, soft and pear shaped, made of plant down densely bound with webs to create soft, felt-like walls. The shape and the soft thin walls, like fine woollen knitting, have led many to describe the nest as being like a baby’s bootee”.
The walls may be thin however they are tough and withstand the rigors of both the young birds as they rapidly grow within the nest and the many visits by the parents, who cling to the nest to supply food and take away waste.
The nest must stand up to the rigors of parents making possibly thousands of visits to the nest and up to four rapidly growing and active young.
This nest was constructed in a Snowy Daisy-bush (Olearia lirata) near the top about 1.6 metres above the ground surface where it was moderately exposed not only to photographers but also to potential predators.
At this nest, only the female came to feed the young.  In this case there were two young, a smaller clutch than the usual three or four? The male was too shy to come near the nest while I was nearby taking photos. It is possible however that the male was supplying the female with food and she was bringing it in to the young while I was there.
Each time the female came in she followed more or less the same path landing on a stem of the Daisy-bush about half a metre from the nest before landing on the nest itself. The young were often aware of her approach well before I was, as they started calling with wide-open mouths thrust out from the nest entrance before she appeared, no doubt they were alerted to her approach by a single call.
The female approaching the nest with mistletoe fruit. She followed the same path on most visits.
She always paused to check all was safe before making the last short flight to the nest.
The young birds in the photos are about a week old and the diet is mostly mistletoe fruits. They were being fed mistletoe fruits before their eyes opened. One fruit was delivered at a time. About every third visit waste fruits were taken away, usually three were expelled at a time by one of the young.
Both chicks were always very keen to be fed. How does the parent know which one to feed? It must be even harder to determine when there are four young.
The fruits were inserted well down the young bird's throats.
The careful removal of waste from the nest is practiced by many bird species, especially smaller birds. Apart from reasons of hygiene and the shear practicality of avoiding large volumes of waste accumulation in small nests, the removal of waste reduces the chance of attracting predators to the nest.
The chicks backed their rear ends well out of the nest entrance before excreting several partially digested mistletoe fruits which the female deftly collected.
Job done, female about to depart with another load of waste, which I assume she dropped somewhere away from the nest on her way to collect more fruits.
A fascinating and closely dependent relationship has evolved between a group of parasitic flowering plants and a single bird species.
When out in the field keep and eye open for mistletoe and wherever you find the plant Mistletoebirds will not be far away. They are fast and active birds not easily seen so learning their calls is a good way to find them. 
Mistletoe also attracts many other bird species, particularly honeyeaters, and nests of many species can often be found in the dense foliage.