Archive for the 'Bird Word' Category

• Irruption: when large numbers of a particular species move to an area where they are not commonly found in large numbers, often in response to drought, rainfall or other environmental changes. In Australia, some species of hawks and kites can irrupt into areas experiencing mouse plagues or locusts. Water birds irrupt into areas experiencing sudden flooding.

An irruption of birds can be a spectacular event. This is something that happens quite regularly in Australia, often as a result of our wildly fluctuating environmental conditions.

Mouse Plague

I can remember back to about 1990 when there was a serious mouse plague in the wheat growing areas east of home. Millions of mice infested sheds and barns on the local farms. During this time we went on a camping holiday to Hattah-Kulkyne National Park.We drove through this area and it was impossible not to run over hundreds of mice as we drove along. In fact, there were so many dead mice on the road, they caused corrugations. It was a rough ride.

Letter-winged Kites:

While we were travelling along we kept looking out for Letter-winged Kites. This species is usually confined to areas much further north. Because of the mice plagues they had moved south in significant numbers and were seen in the area we drove through. This Kite is a rather hard species to find normally. I was excited at the prospect of seeing at least one. I still haven’t seen one. [sigh]

Black-tailed Native-hens:

On other occasions I have seen large numbers of other species. I remember seeing literally thousands of Black-tailed Native-hens on the road south of home on our way to Meningie. Normally we might see two or three. At other times Australian Pelicans have been known to breed up in huge numbers, especially after flooding in some areas.

Lake Eyre in flood:

As I write this in mid-March (2007) Lake Eyre in far north South Australia is filling with flood waters from heavy rain in parts of Queensland. This lake is usually a dry salt lake. Over coming months, many species of water birds will breed in massive numbers in response to this water. In a year or two, as the lake dries out, there may well be an irruption of some of these species as they move in large numbers to other parts of the country.

• Gregarious: some birds live in groups and are said to be gregarious. One such species is the White-Winged Chough. They are usually seen in groups of from 5 to 10, though the family group that visits my garden has been up to 12 in size. I have seen larger groups than that in other places.

There is some truth in the saying “birds of a feather flock together.” In Australia it is quite common to see large flocks of birds of the one species. There are few sights as beautiful as a flock of several hundred pink Galahs wheeling through the deep blue Australian sky. Corellas and cockatoos also flock together, feeding together on the ground in large groups numbering in the hundreds, or even thousands.

Galah

Another amazing sight is to see a large flock of budgerigars feeding together. As they fly off – sometimes in their thousands – it is like a swiftly moving green cloud before your eyes. When such a flock lands in a dead tree, it suddenly seems to spring back to life once again.

Budgerigars, Cleland Wildlife Park

Some of our finches are also quite gregarious. These flocks may only number in the dozens but in their own small way can be just as spectacular. They bring great delight to the observer when such groups visit a watering point (such as a bird bath) or a feeding tray in a park or someone’s garden.

Zebra Finch

Waterbirds can also be said to be gregarious, their numbers can often be in the thousands. Rafts of ducks, mudflats seething with waders and nesting cormorants in their thousands can be an inspiring sight and an attack on the ears (and nose in the case of cormorants).