Captain Hutton says:-"This species arrives in the hills up to 7000 feet at least, in April, when it is very common, and appears in pairs with something of the manner of a phylloscopus.
"The Nests and Eggs of Indian Birds, Volume 1"
Allan O. Hume
P. viridanus is an inhabitant of brushwood ravines, at 9000 and 10,000 feet elevation; while P. tytleri is exclusively a pine-forest phylloscopus.
"The Nests and Eggs of Indian Birds, Volume 1"
Allan O. Hume
As far as the colour goes, the representations in Hewitson's work of the eggs of Parus cristatus, Parus coeruleus, and phylloscopus trochilus will give a very correct idea of the different varieties of the egg of the present bird.
"The Nests and Eggs of Indian Birds, Volume 1"
Allan O. Hume