I had a 24-hour layover in Thiruvananthapuram (Trivandrum) 5-6 January 2019 and decided to head to Arippa, 65 km with car north-northeast of downtown Trivandrum. A nice walk was had, the results can be seen here: https://ebird.org/view/checklist/S51337179
I photographed 3 species of Phylloscoups, one which seems straight-forward, and two that I would like to get some input on. Apparently, 6 species winter here regularly, and listed here in what I feel is in order of greatest likelihood looking at eBird:
Green Warbler, Phylloscopus nitidus Seems abundant in the whole w and sw India. Greenish Warbler, Phylloscopus trochiloides viridanus
Seems abundant in the whole w and sw India.
Large-billed Leaf Warbler, Phylloscopus magnirostris
Seems common in w and sw India.
Western Crowned Warbler, Phylloscopus occipitalis
Seems fairly common in w and sw India.
Tickell's Leaf Warbler, Phylloscopus affinis
Seems scarce in the Trivandrum area, more common further north
Tytler's Leaf Warbler, Phylloscopus tytleri
Seems scarce in the Trivandrum area