Ian’s Bird of the Week – Great Frigatebird ~ by Ian Montgomery
Newsletter – 8/28/14
This week’s good news is that the ebook Where to Find Birds in Northern Queensland is now available on the iTunes store (in 51 countries). So if you have an iPhone, iPad, iPod Touch or Mac (running OS X Maverick) this is for you! Here is the link: https://itunes.apple.com/au/book/where-to-find-birds-in-northern/id912789825?mt=11&uo=4. To make a connection with this week’s bird, the Great Frigatebird, here is a screen shot from iBooks to show you what you can expect. All the text items highlighted in purple and links to either other places in the book – typically places, birds or lists – or external websites. The images are the same size as the ones that are included in the bird of the week, so if you double-click, or double-tap, on them, you can enlarge them to full size.
If you think about birds in northern Queensland, perhaps iconic rainforest species like the Cassowary or Victoria’s Riflebird come to mind. Fair enough, but there is much more to this region than rainforest, important though that is.The area also has wonderful wetlands, tropical savannah forest, mountain ranges, dry country habitats and, last but not least, the coast with its Barrier Reef, beaches, mangroves, mudflats, continental islands and coral cays. So it should be no surprise that over 400 species of birds occur here and you need a reference devoted to the region to do it justice. I’ve chosen a dramatic seabird to make the point.
The term ‘frigate’ was first applied in the 17th century to warships built for speed and manoeuvrability and frigates were often used by pirates to attach merchant shipping. Frigatebirds, also called Man o’ War Birds, got their name for their piratical habitats of harrying other seabirds like boobies and tropicbirds to make them drop their prey. In fact, studies have shown that piracy accounts for perhaps only 20% of their food, and they are expert fishers as well. They fish by snatching prey, such as squid and young turtles, from the surface of the sea or in flight, in the case of their favourite prey, flying fish.
Despite their naval name, frigatebirds are wonderfully adapted for flying and are poor swimmers to the extent that they are reluctant to land on water, as they can take off only in strong winds and their plumage is not waterproof. They have very light bones making up only 5% of the body, huge pectoral muscles, enormous wing area, long forked tails for rudders and streamlined bodies with small heads. Despite their size, they are very light, soar effortlessly in good winds and are very acrobatic. Female Great Frigatebirds, larger than males, are about 1m/40in long, have a wingspan to 2.3m/90in but weight only 1.2-1.6kg/2.6-3.5lb.
The male Great Frigatebird, first photo, is the only all-black frigatebird occurring in Australia – the other all-black males are the Magnificent Frigatebird of Atlantic Ocean and the eastern Pacific and the Ascencion Frigatebird of the east Atlantic. Frigatebirds are unusual among seabirds in drinking freshwater if they can get it, and this male is drinking at the mouth of freshwater stream on Christmas island by snatching a beak-full of water in flight. Frigatebirds also bathe in flight by splashing into the surface of the water and flying off. You can also see its red gular pouch. This is inflated to enormous size to impress females during courtship. I haven’t got a photo of displaying Great Frigatebird, but you can see a Magnificent Frigatebird doing so here: Magnificent_Frigatebird.
Female Great Frigatebirds have white breasts and care needs to be taken in distinguishing them from other female and juvenile frigatebirds – Lesser Frigatebirds of both sexes have white ‘spurs’ in the axil of the underwing, and Christmas Island Frigatebirds of both sexes, have white bellies. Birds in Indian Ocean waters in Australia belong to the nominate race minor, distinguished by the females having pink eye-rings, second photo. Birds in the Pacific belong to palmerstoni and usually have blue eye-rings, third photo, though doubt exists as to the validity of the races and the reliability of the fieldmarks.
Because of their need for consistent winds, frigatebirds are restricted to tropical waters where they can rely on the trade winds. Adults are sedentary and remain close to their roosting sites and breeding colonies, mostly on small isolated islands. Non-breeding birds and immature birds are pelagic and move over huge distances. Trade winds are unusual in that they form cumulus clouds and hence thermals over water both by day and night, and frigatebirds make great use of these to soar as high as the cloud base and will fly at night if conditions are right. Pelagic frigatebirds use the front of storms to move around and can cope with high winds very well. This is why they appear in coastal areas after cyclones and are supposed to be called ‘rain-brothers’ by Australian aborigines, though I haven’t been able to verify this.
The range of the Great Frigatebird includes the tropical Pacific, southern tropical Indian and western Atlantic Oceans. In Australia it breeds colonially on islands along the outer Great Barrier Reef, in the Coral Sea and on Christmas and Cocos (Keeling) Islands in the Indian Ocean, usually in mangroves. The juvenile in photos five and six was photographed on East Diamond Islet, about 600km east of Cairns http://www.satelliteviews.net/cgi-bin/w.cgi?c=cr&UF=34304&UN=456541&DG=ISL. Breeding birds form pair bonds and both parents share in the incubation and feeding of the young. The young develop very slowly. This is thought to adapt them to periods of starvation when the adults have trouble finding food, and remain under parental care for many months.
The last photo shows a hapless Red-tailed Tropicbird near Christmas Island being harried by a female Great Frigatebird who has grabbed it by the tail-streamers. Frigatebirds hang out near seabird colonies waiting for birds carrying prey or with full crops returning to feed their young. It’s hard enough work being a parent without having to put up with this!
Ian Montgomery, Birdway Pty Ltd,
454 Forestry Road, Bluewater, Qld 4818
Tel 0411 602 737 firstname.lastname@example.org
Bird Photos http://www.birdway.com.au/
Recorder Society http://www.nqrs.org.au
but those who trust in the LORD will renew their strength; they will soar on wings like eagles; they will run and not grow weary; they will walk and not faint. (Isaiah 40:31 HCSB)
Thanks again, Ian, for introducing us to another interesting bird. We have seen the Magnificent Frigatebirds here in Florida, but these Great ones are also amazing. That fact about only 5% of their weight being the bone structure is another fantastic design from their Creator.
Frigatebirds belong to the Fregatidae – Frigatebirds Family which only has five species in it.
Fregatidae – Frigatebirds Family
Great Frigatebird – Wikipedia