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I've been a Canberran since moving here from Adelaide on the first day of 1980. I now live in suburban Duffy with my partner Louise Maher, ABC 666 radio and on-line journalist. Among my early memories is following Sleepy Lizards (Shinglebacks) around the paddocks north of Adelaide, guarded by the faithful bull terrier. I have always been passionate about the natural world, trying to understand how it works, how the nature of Australia came to be, and sharing those understandings. My especial passions are birds, orchids and mammals. For much of my life I have been a full-time naturalist, running bush tours, writing books etc, doing consultancies, presenting a regular radio slot on local ABC, chairing a government environment advisory committee and running adult education classes. Recently I have eased back somewhat, but am still writing, teaching, doing some radio work and running overseas tours - as part of my fascination with our Gondwanan origins I've been running tours to South America for the past decade. I was awarded the Australian Plants Society Award in 2001 and the Australian Natural History Medallion in 2006, both for services to education and conservation. In January 2018 I was awarded a Medal of the Order of Australia for 'service to conservation and the environment'.

Thursday, 9 August 2018

Mangroves #3: life above the mud

This post marks the completion of my three-part series on mangroves, one of my favourite habitats, not least because they are so unfamiliar and even unlikely, fluctuating with the tides between land and sea environments. Moreover they are some of the richest habitats on earth, being the cradle of uncountable millions of organisms which begin life feeding on and in the nutrient-rich mangrove muds. While I don't regard that as the best reason to protect them, mangroves are the essential basis of many of humanity's richest fisheries and prawn industries.

The series began here, and you might want to have a look there if you've not already done so, as there is background information that I won't repeat. And the second post featured some seriously cool crabs!

Today I want to introduce some animals that live above the mud, in the mangrove trees themselves. Some virtually never leave the mangroves, to others the mangroves are a very significant part of their lives though they venture beyond them too. Many feed and breed there, some come back every day to roost. 

Quite a few tropical birds are mangrove specialists, including in Australia. Here are a few.

Mangrove Robin Peneoenanthe pulverulenta, Bayview, Darwin. This lovely bird, with a sad whistle,
never leaves the mangroves; it is found in northern Australia and New Guinea.
In addition to insects, it eats small crabs. It is the only member of its genus.
Mangrove Grey Fantail Rhipidura phasiana, Norman River, Karumba, Gulf of Carpentaria, Queensland.
It is closely related to the familiar Grey Fantail, but has a paler grey back, broader wing bars and a shorter tail.
It too rarely leaves the mangroves of northern Australia and southern New Guinea.
This was from a boat trip that I mentioned in the last post, as are the next two species.
White-breasted Whistler Pachycephala lanioides. This is a female, he has a magnificently snowy breast
and throat, separated by a black collar. Another mangrove specialist, found across northern Australia.
Immature male Red-headed Honeyeater Myzomela erythrocephala.  (There is a tendency elsewhere to use Myzomela
as a group name, but fortunately we've resisted that so far in Australia!) This one again lives wherever there
are mangroves throughout far northern Australia and across Torres Strait.
The glorious adult male below, though largely hidden, gives some idea of what this youngster will later look like.

Others, as mentioned, forage to a significant degree in mangroves, but aren't so restricted. The following birds are typical of these. The first two in fact spent time inspecting us as we sat on the platform at the end of the excellent boardwalk at the East Point mangroves in Darwin (see first post in this series for more on this great spot, but I also did a whole post on it, here).
Lemon-bellied Flycatchers Microeca flavigaster, which are actually robins (though a recent attempt
to persuade us to called them flyrobins isn't gaining much traction yet). In the Northern Territory they are
largely mangrove birds, but elsewhere in northern Australia and especially in New Guinea they extend
into other woodland and forest habitats.

Northern Fantail Rhipidura rufiventris; similar comments could be made about this friendly little chap
as per the others, though it's found well beyond the mangroves in the Northern Territory too.
(The early morning light under the canopy wasn't too great.)
Varied Honeyeaters Gavicalis versicolor, Cairns Esplanade. This busy and garrulous honeyeater does spend
most of its time in mangroves, but regularly moves out into nearby coastal vegetation, including in
parks and gardens, as here.
Shining Flycatcher Myiagra alecto, Gunlom, Kakadu NP, Northern Territory (male above, female below,
in a very impressive example of sexual dimorphism). A beautiful bird which can be quite curious,
nearly always near water, either in mangroves or along stream lines.
Collared Kingfisher Todiramphus chloris, Selingan Island, Sabah.
This lovely kingfisher is mostly found in mangroves - in a huge range from north-east Africa to
the Lesser Sundas (Bali, Lombok etc) - but does use other habitats, especially on islands.
We used to think it had an even larger range, to northern Australia and well out into the Pacific, but
recently five species have been split from it, including the Torresian Kingfisher T. sordidus of northern
Australia and New Guinea, which is strongly associated with mangroves - in fact
it's often been known as Mangrove Kingfisher here. Crabs are a specialty!
Stork-billed Kingfisher Pelargopsis capensis, Sabah, Malaysian Borneo. A magnificent bird,
found from India to the Philippines and the Lesser Sundas. A fish and crab specialist,
particularly in mangroves, but it is broad-minded and expands both its habitat and diet beyond that.
Not only birds are mangrove specialists however.
The extraordinary Proboscis Monkey Nasalis larvatus, endemic to Borneo, is mostly dependent on mangroves,
especially their leaves and fruit, though it is also found in riverine forest. Here at Labuk Bay, Sabah.
Proboscis Monkey youngsters at very boisterous play.

Silvered Leaf Monkeys Trachypithecus cristatus with baby (isn't it an amazing colour?!),
Bako NP, Sarawak. These lovely monkeys specialise even more in leaves than the Proboscis do,
and share their coastal, especially mangrove, and riverine forest habitats.

Water Monitor Varanus salvator Klias River Sabah. This big goanna is widespread in south and
south-east Asia, especially in mangroves, but also beyond them.
Some species, which don't otherwise utilise mangroves, nest in them. This is especially true on isolated volcanic islands where other trees may be scarce.
Red-footed Booby Sula sula (white morph) nesting in mangroves, Genovesa, Galápagos.
This was part of a busy colony in the mangroves just behind the beach, below.

 Others just roost there.
Striated Heron Butorides striata (also known as Mangrove Heron) here roosting in mangroves,
Isabela, Galápagos, though in fact they feed there as well when the tide drops.
Papuan Frogmouth Podargus papuensis, at day roost in mangroves, Centennial Lakes, Cairns.
Some of the most dramatic roosting colonies in mangroves are provided by fruit bats, which can number tens of thousands.

A very small part of a huge Little Red Fruit Bat Pteropus scapulatus colony, in mangroves along the waterfront
in Cooktown, north Queensland. By day they sleep (and squabble) and in the evening spread out over the
countryside in search of fruit and nectar.
So, mangroves. I hope you can be as excited by them as I am. And if you're still an agnostic, maybe you could visit some soon and see if that helps. Meantime, thanks for exploring them with me.

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Flabmeister said...

I have checked and don't think I have missed it, but you don't seem to have commented about the value of the mangroves as a fish breeding habitat. My understanding this was one of the huge benefits (called "Values" by bean counters) of the mangrove environment.


Ian Fraser said...

You're absolutely right, and it should have been in one of the first two instalments. I'll find a way to put in here, where it's more likely to be seen by those who have already perused that earlier ones. Thanks for this!

Ian Fraser said...

See new first para.