Tawny Frogmouth Trio

A Tawny Frogmouth flies onto her nest with a large spider to feed to her chicks

During my study of Tawny Frogmouths Podargus strigoides I have collected 342 nest records and most of those have been by pairs of birds. However, four have been by trios of birds, one of which from this year is shown here.

The two females have roosted together all breeding season, about fifty metres from the male on the nest

Two females have been together with a male since the beginning of the nesting season and they are readily identifiable from one another as one bird is grey and the other has much more rufous in her plumage, especially on her wing coverts and scapulars. I didn't know whether these extra birds in breeding groups take part in rearing the young, so I watched this group over a few nights to see if all three birds fed the chicks. Under a quarter moon, there was enough light to see the three birds fly in and feed the chicks and I recorded the incidents with flash photography for confirmation.

The male sits on the nest all day - note his bold markings on a pale grey background plumage colour 

The male was easy to identify as his markings are very bold on his overall light grey body plumage, especially on his breast. At night, under flash, these contrasting markings are even more boldly emphasised. He, like all other male frogmouths which I have recorded at nests, regularly took his turn at feeding the chicks.

The male is readily identifiable by his large size, strongly contrasting plumage and well-speckled breast

When the birds landed with their backs to the camera, they could be identified by the colour of their wing coverts and tail feather patterns. The females were noticeably smaller than the male and they could be seen to bring in prey and feed the chicks which gave soft begging calls as they took the food from the adults.

The red female feeds the chicks 

Here the red female can be seen feeding the chicks, then nine seconds later, the grey female flew in and the red bird took off to the right over the camera. The incoming female can be seen carrying a beetle in her bill.

The red female leaves the nest as the grey female flies in with food

One feature that could only be detected with the photography was the difference in wing feather moult between the two females. The red bird had complete, fully grown primaries, secondaries and tail feathers. The grey bird was moulting three inner primary feathers, with moult scores of 4, 3 and 3, all the rest were complete, more likely old rather than newly-grown as most birds moult post-breeding.

The grey female leaves the nest, showing that her inner primary wing feathers are in moult

These differences in the birds moult were best captured in shots of the birds leaving the nest when they had opened their wings fully on take-off, compared with when they closed their wings on landing.

The red female leaves the nest, showing all primary, secondary wing feathers are fully grown and her tail is complete 

Other data which I collect when watching these birds at night are the frequency at which the chicks are fed, over the whole night, by the different sexes of adult, under various weather conditions etc. It will be a while before I collect all that data though.

Another shot of the red female leaving the nest and showing her complete wing feathering

Precocial and Altricial young

Birds in Scotland are busy hatching and rearing their young at the moment, with June being the month when most species have dependent young at some age. I have been ringing, with other members of the Grampian Ringing Group, various species of chicks from common and tiny Willow Warblers to large and rare Golden Eagles, and all sorts between. While doing so, I have as ever been impressed by how well each species has adapted the best method of post-egg development to suit its lifestyle.
 

Common Gull eggs, with cracklines and holes - the chicks are beginning to hatch

I have been ringing gull and wader chicks and took a sequence of photographs at one Common Gull colony to show the development of their chicks. The typical clutch size is three eggs and the chicks hatch one after another, over about two days. The first chick to hatch stays in the next and are brooded by the adult birds until the last chick hatches and dries. Then they all begin to wander from the nest, usually set on the ground, and hide beneath the surrounding vegetation.

One dry chick, one wet chick and one still on its way out

Gull chicks have cryptically-coloured down which keeps them concealed from predators and warm. They can walk sand run strongly and are known as precocial young.

A fully dry Common Gull chick - two days old and now three metres from the nest

Or rather, gull chicks are better described as Semi-Precocial young, those which are downy and can walk and can leave the nest soon after hatching. e.g. in the case of terns and gulls, although they still rely on their parents for heat and nourishment.

True fully precocial, self-dependent young would be such as Mallee Fowl which find their own food without even guidance from either parent.

This is so different from the familiar nestling birds, which are Altricial - where the young are naked, blind, weak-limbed at hatch and rely totally on their parents for food and heat.

Semi-altricial young such as raptors are downy at hatch, but weak and rely on their parents for heat and food.

Four Skylark chicks in their nest

Two other terms which are used to describe young birds are; Nidifugous - those that leave the nest soon after hatching, generally once the whole brood has hatched and their down dried, and Nidicolous - those which remain in the nest for several days or weeks after hatching.

A three-day old Skylark chick, still partially naked and blind

The nestling stage is a very vulnerable period for young birds and the variety of concealment and protection methods taken by the parent birds is, to me even more fascinating. From secretive single nests to noisy colonies, each works for the protection of different species. But more on that later.

Five kestrel chicks - ranging from about one to two weeks old

The Tawny Frogmouth chicks have fledged

To watch a video of the chicks about to fledge click here 

(approx. 4min., 10 Mb)

The Tawny Frogmouth chicks which featured in the previous videos have now fledged. On the night of the 29th October, under a big fat full moon, they emerged from under the adult male who had been covering them all day. They quickly scrambled along the nest branch and seemed so, so pleased to be able to move around in the dark. There was lots of wing-stretching and flapping and eventually the eldest took a short 'first-flight' across to another branch. As the light dimmed, the magpies and currawongs finished their dusk chorus. Then all that could be heard was the hoarse coughing and wheezing that the chicks made as they jostled for position or begged for food whenever an adult flew in with a morsel of prey (still unidentified).

To watch a video of the frogmouths at dawn click here

(approx. 2min., 5Mb)

By dawn, there was only one chick left at the nest and the male flew in to protect it as the sun cast the first pink beams onto the birds. The other two chicks were sitting on a branch below the camera, safe, next to the female. Frogmouths incubate their eggs as soon as the first one is laid, so the youngest one was about two days younger and less developed than the others. But it would be gone the next night. All the while the other local birds were chattering and whistling in their dawn chorus.

Fall from nest

Two tawny frogmouth chicks fell with their nest as it dropped out of a branch fork during heavy rain last night. They are only about three weeks old and would have been in the nest for at least another week. Even then they are dependent upon their parents for another month after that. 

Fortunately their father gathered them onto a log by morning where they were sitting, all nice and warm and dry. And safe from foxes and hopefully cats.

 

The chicks were well dried and warm although it was still raining.

They offered a splendid photo opportunity.

The adult female sat quietly in a tree 30m away, watching all the time.

Tawny Frogmouths 2011

The first of the tawny frogmouth chicks have fledged, or rather left the nest. They are dependent on their parents for another month yet, as they fly around their territory in short flutters between trees.

 A male frogmouth sits with a chick recently out of the nest - one metre away in the fork on the right.

This was on the 14th October.

 A female frogmouth watches over her mate on the nest fifty metres away in the next tree.

Two female frogmouths roost together while a male sits on chicks in a nest nearby. Who is the mother of the chicks? Is the second female tolerated because she is a daughter from  last year's nest. The birds are identified as females by the red/rufous on the their neck and epaulets. The males are more uniformly grey.