© Nesting Common Tailorbirds- One Full Circle Part 4

posted in: Morphology-Develop. | 0

Part 1; Part 2; Part 3; Part 4: Plumage on Parade.

“Breeding season is a serious affair – an ultimate for birds to procreate their own species. It is also the best time to observe them. During this short window period, hormones peak and stimulate birds – mostly males’ plumage to transform into its best of colour and sheen. Some bare parts in several bird species too change to become attractive to females.

“As chase began and female courted in fervent, at times competitively chasing away other males, the pursuing male simply had to be at its ‘Sunday’s best’.

“Both Otto and Satori’s plumage can simply be described below in pictures.

“Wearing partial caps of cinnamon-rufous, featherings fade to grey on face and neck to include random brush of olive colour over the latter.

“Here are male and female plates for comparison.

Cap: male.
Cap: female.
Neck: male.
Neck: female.

“Ear coverts of slaty grey ruffled with white feathering, more shaft streaking noted in male.

Ear coverts: Male.
Ear coverts: female.

“Of bare parts of the heads, both sexes have upper mandibles of partial blackish horn. Equal lengths with lower mandibles show pink to match with pale, thin tongue and mouth lining.

Mandibles, tongue and mouth lining: male.
Mandibles, tongue and mouth lining: female.

“Eyes – like a sun eclipse, pupils black outlined by a ring of pale orange. Iris is brick brown with eyelid rimmed orange, surrounded by a corona of sunburst eyelid feather follicles (below). In some images, Otto’s eyelid rim appeared more orange than Satori.

Eyes.

“While both spotted full white throats, interesting observations included presence of inflated black, lateral pouch during singing. Bare parts of black lateral throat also exposed during neck extension.

Throat pouch: male.
Throat pouch: female.

“Below white chin and throat to breast, Otto appeared to present greyer feather streaking on sides of breast as compared to female Satori. However, a misleading of downy feathers gone disarray cannot be discounted. One photograph revealed basal end of downy feathers on breast areas to be greyish black and upper half end white. Belly to vent featherings are well represented appearing all white in both birds.

Breast and belly-vent: male.
Breast and belly-vent: female.

“Under good photographic, lighting conditions, the colour of olive green on birds’ back is well represented with over splash onto brown wings and upper tail coverts.

Back, wing and tail: male.
Back, wing and tail: female.

“In wing spread position, Otto’s posed ten Primaries and Secondaries on either side. Upper wing coverts were of brown-grey variables.

Wing spread: male.
Wing spread: male.
Wing spread: female.

“The wing bend lining of both birds is white. It is an important identification, point feature as some species of Tailorbirds e.g., Dark-necked Tailorbird (Orthotomus atrogularis) is presented in yellow.

Wing bend: male.
Wing bend: female.

“Under wing coverts of both birds appear to look buff white with grey–black armpits.

UNder wing: male.
UNder wing: female.

“Grey flanks of Otto and Satori represented here with latter showing more buff at outer edge.

Flank: male.
Flank: female.

“Posterior end of female appears more buff while Otto shows near all white.

Rear: male.
Rear: female.

“Shanks of both birds show few white feathering with bare skin pink. Knee joints appeared more orange at nest breeding stage. Tarsals pink ending with four clawed toes- three forward, one rear as most passerines do.

Feet: male.
Feet: female.

“What did Otto and Satori do during their breeding cycle? How did they communicate? How did they perched without breaking a stem or sent foliages to sway? Why do parents clean house before vacating their nest?

“Join Avian Writer in Part 5 to read more into the bird life of Otto and Satori- breeding pair of Common Tailorbirds Orthotomus sutorius.”

AVIAN WRITER DAISY O’NEILL
PENANG MALAYSIA
22nd July 2019

COPY OF COPYRIGHT ARTICLE AND ALL IMAGES – COURTESY OF DAISY O’NEILL BIRD CONSERVATION FUND

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