Indian paradise flycatcher -plumage polymorphism in male

Check out part-1 of this series –https://anukusumkadri.9sh.org/2020/06/20/amazing-birds-and-truly-amazing-facts-of-birds-indian-paradise-flycatcher/

Many species show polymorphisms, which are often sex-related. However, there are also polymorphisms within a sex — these may be related to age or may be stable throughout their life. Which one of these depends on the function of the polymorphism.

Indian Paradise Flycatcher (Terpsiphone paradisi). Males of this species have two morphs: rufous and white. Both are with long tail streamers.

There are several hypotheses about these male morphs.
*One notion is that juvenile males are rufous, and that they moult in the third year into white morph adults.
The existence of intermediate form (intermediate between the two morphs)is an evidence for morph relating to age.

*Another hypothesis is that the morphs are not due to age, but instead of coexistence with each other.

*The third hypothesis is, it includes elements of the previous two, that is that juvenile males are rufous, but moult in the third year to either rufous or white.

In general

*The females are cinnamon above with a grayish throat, dirty white below, a shorter tail, and they have black eyering which makes them look dull, grey bill and grey feet. (See the photo attached)

*Juveniles/young males are rufous and have short tails. They have blue eye ring, the head, face, crown, crest and nape are glossy black. The throat is black ( See the photo)

*The adult males exhibit plumage dichromatism. They are either predominantly bright RUFOUS abovementioned or predominantly WHITE.
The edges of the wings and tail feathers are sometimes black.
The head, face, crown, crest and nape are glossy black. The throat is black in males, the bill is black. The males have blue eye-ring, the legs are gray.

*Intermediates of both forms also exist. ( See the Photo)

*Some birds also molte from rufous into white plumage. (See it in the photo attached)

According to Summer Research Fellowship Programme of India’s Science Academies
the possibility of age related polymorphism within this framework, and suggest that young birds are rufous but become white adults in the north but remain rufous in the south.

Reference collected from:

http://www.reports.ias.ac.in/report/19978/investigating-male-plumage-polymorphism-in-indian-paradise-flycatcher
Dr. Suhel Quader
Nature Conservation Foundation, No.361 ‘Hari Hara’, 5th Main Road, 1st cross Road, Kodigehalli, Bengaluru, Karnataka, 560097

A. Civin Solomon
Bharathidasan University, 196/236, Joshua Street, Opposite to YMCA, College Road, Nagercoil, 629001

https://en.m.wikipedia.org/wiki/Indian_paradise_flycatcher

Indian paradise flycatcher is a eye catching bird, which turned me into a bird watcher since 2017. My encountering these birds, and all my observations are purely from the wild and each film recording spontaneous from nature direct during 2017 – 2020 in my Sunday birding trips in outskirts of Bangalore. I have attached Photographs borrowed from Mr Devadatha Kumar SR my batch mate and guide in this article.