Here we present the year-wise arrival pattern of one of our most observed species – the Greenish Warbler.

As in our earlier illustrations, each sighting is shown as a vertical black line.

The above graphic shows that Greenish Warblers start their southward migration into the Indian subcontinent in late August. They stay on till early summer and by May almost all of them return to their breeding grounds in the Himalayas and beyond.

To look at all the Greenish Warbler sightings on MigrantWatch please click here. You may also want to look at our series on Phylloscopus warblers here.

Continuing with the series of extracts from Douglas Dewar’s A Bird Calendar for Northern India, published in 1916, here is his lyrical description for February.

* Current name: Grey-headed Canary Flycatcher.

Taken, with grateful thanks, from Project Gutenberg.

Below is a photo of a Grey-Headed Canary Flycatcher taken by MigrantWatcher Jatin Shrivastava near Jalgaon, Maharashtra.

Continuing with the series of extracts from Douglas Dewar’s A Bird Calendar for Northern India, published in 1916, here is his lyrical description for January.

* Current name: Grey-headed Canary Flycatcher.

Taken, with grateful thanks, from Project Gutenberg.

By Mousumi Ghosh
Read Part I in this series of articles on leaf warblers

Wintering Season

To most of us, Phylloscopus leaf warblers belong to just one size category: tiny! And confusing. Every winter, these diminutive and inconspicuous birds envelope the subcontinent in a wave, migrating thousands of kilometres south from their breeding grounds in the Himalayas and beyond. Migrating long distances takes a lot of energy, particularly for smaller species. Small differences in body weights among species make a huge difference in deciding how far they have to travel for wintering. Small-sized warblers are geared to feed on small insects, which are available in good quantities right from the Himalayan foothills all the way down south. The larger Phylloscopus warblers (like Large-billed, Greenish, and Western-crowned) do not have it so easy, as their preferred food – large insects – are available in adequate supply only further south. Hence, in the wintering season smaller species don’t travel very far, with their southern limit being either the sub-Himalayan foothills (e.g. Lemon-rumped Warbler) or mostly up to Central India (e.g. Hume’s Warbler), where wintering ranges of larger species begin. In contrast, larger species  (e.g. Greenish and Western Crowned Warblers) travel farther south and all way to southern India and Sri Lanka.

A great deal of knowledge about the wintering ecology of Greenish Warblers has emerged from Madhusudan Katti’s work in the Kalakkad-Mundanthurai forests of Tamil Nadu. He found that individual birds, quite remarkably,  come back to the same wintering territory year after year!  Also, in years of scanty rainfall and limited food the birds were unable to eat enough to moult in time for their long journey back to their breeding sites. This shows how conditions in their wintering habitats may influence whether birds are able to make it back to breed; and this has obvious implications for the size of the population.

Several parallels exist between the way these birds breed and winter. For example, the species which breed on “top of the mountains” (Hume’s  and Greenish Warblers) spend the winter on “top of the trees”. Interestingly, while these two species are territorial in winter (both males and females defend territories), others, like the Western-crowned and Lemon-rumped Warblers, join mixed-species flocks. Although most species spend their breeding and wintering seasons in drastically different forests, they use similar foraging techniques. For instance, the Lemon-rumped Warbler (which breeds in conifer-mixed forests and winters in sal forests), mostly captures prey by hovering in the outer foliage of trees in both seasons.

Breeding Season

The Himalayas, because they provide such a huge variety of habitats, harbour one of the richest communities of leaf warbler species in the world. Twenty-one out of  the world’s 61 species of Phylloscopus are found in the Himalayan region. They occupy the entire range of habitats from tropical evergreen/deciduous forests in the foothills to the alpine meadows above the treeline. In the Himalayas the elevation zone 2500–3000 m supports the highest diversity of breeding warblers, where up to 9 species may breed together.

How do so many similar species coexist in one place? One reason is that while superficially leaf warblers are very similar, different species possess differently sized body parts. This is associated with differences in foraging behaviour. For instance, larger species eat larger insects and species with wider beaks catch more flying insects. Another way to allow coexistence is by occupying different elevation zones. To avoid competing for similar food using similar methods, each altitudinal zone in the mountain typically has one large species, a medium species and a small species, which capitalize on prey in accordance to their body sizes.
The overall drab colours of leaf warblers conceal subtle differences which not only indicate the habitat that they breed in, but also help in communicating and selecting mates. To the trained eye, visually distinguishing most of the leaf warblers involves relying on presence, number and colour of brighter patches such as wing bars, supercilium, rump patch and crown stripes. Species occurring in dense habitats, such as the Lemon-rumped Warbler, typically possess many bright patches (two wing bars, a distinct supercilium, crown stripe and rump patch). Such warblers often flash these patches to communicate. Additionally, males with brighter and longer wing bars are of higher quality (such males occupy larger territories) and are preferred by females. On the other hand, the Tickell’s Warbler, which breeds in open Juniper scrub, has no bright patches at all.

To be continued…Coming up next in this series: Tips for Identification of Phylloscopus Warblers

By Mousumi Ghosh

When I started birding seriously in the year 2005 after joining the Master’s course at the Wildlife Institute of India, I conveniently ignored every warbler I saw. Since visual identification was very difficult (given their frustratingly similar and drab appearances), I was happy enough to say that so-and-so bird was of a warblerish persuasion, and leave it at that. But then, as fate would have it, I wound up studying the wintering ecology of three species of leaf warblers in the Himalayan foothill forests of Himachal Pradesh for my MSc dissertation. While my primary motivation was to understand how they survive the winter sharing dwindling food resources, I now had to identify them accurately for my work to make any sense.

In most situations a bird in hand is worth two in the bush, but when it comes to identifying leaf warblers it is better to have a bird singing in the bushes than have even ten in your hand! This wisdom came to me from my supervisors Mr. Pratap Singh and Dr. Dhananjai Mohan, who taught me how to identify leaf warblers in the field from their calls and song.

These remarkable little birds belong to the family Phylloscopidae, whose members are dressed in various hues of dull green, yellow, grey and occasionally bright chestnut (as in the Chestnut-crowned Warbler). They are among the commonest species of European and Asian forests. The word Phylloscopus literally means ‘looking into the leaves’ and this aptly describes our industrious friends, who spend almost 75% of their waking hours searching for insects among the leaves. 

The genus is famed for its astounding diversity: more than 60 species of Phylloscopus are described. Most of them breed in the temperate areas of Europe and Asia. Despite weighing only 5-10g, some leaf warblers migrate over thousands of kilometres to arrive in their wintering quarters in the tropics of Africa and South Asia, including the Indian subcontinent. To cite an example, Hume’s Warbler (weighing just about 6 g) covers almost as much distance as the celebrated Siberian Crane (weighing 6 kg) to reach the plains of India from where it breeds in Siberia!

The same attributes which make them so difficult to identify (so many species, yet so similar in appearance) have made them one of the most well-studied groups of birds in the world. Within India, detailed studies of their breeding (in the Himalayas) and wintering ecology (Himalayan foothills, peninsular India) by Dr. Trevor Price and his students have revealed a great deal about these leaf warblers in both breeding and wintering seasons.

Read Part II of this series of articles on leaf warblers

By Raman Kumar

While the details of bird migration are still somewhat mysterious, the broad patterns are reasonably well-understood; for example the direction of migration. The main reason why most migratory birds follow a north–south path is simple: they follow the seasonal patterns in availability of food and breeding resources. Most migratory birds follow this general pattern: (1) breed at higher latitudes during spring-summer; (2) when days start to get shorter and conditions harsher, fly to kinder regions in the tropics.

But there are some species of birds that scoff at these conventions; instead of migrating along a north–south trajectory, these birds move east–west. Among the more celebrated of such “misfits” is the Pied Cuckoo which shuttles east–west between northeast Africa to north and central India. However, there is a lesser-known bird that shows this kind of unconventional migration – the Spot-winged Starling (Saroglossa spiloptera).

This starling, formerly known as Spottedwinged Stare, is unfamiliar to birders from peninsular India because its distribution is limited to the sub-Himalayan and Himalayan region. Unlike mynas and most other starlings the Spot-winged Starling is sexually dimorphic: the male is a dark brownish-and-chestnut and the female is markedly paler. Both sexes sport a prominent white wing patch, giving the bird its name.

In the Western Himalaya the Spot-winged Starling appears in late spring, feeding at fruiting and flowering trees. Small groups are often seen guzzling nectar from the blossoms of trees such as the Indian Silk Cotton. The Spot-winged Starling usually chooses open forests at elevations near 1000 m in Himachal Pradesh and Uttarakhand for breeding. Birdwatchers have seen Spot-winged Starlings at roughly the same spot in successive years, suggesting that they may remain faithful to the same place year after year, but this remains to be verified.

Sightings become rarer in June and by July the bird virtually vacates its breeding quarters. This is the period when the Starlings are believed to make their eastward passage through Nepal and Sikkim. After this hopping flight of thousands of kilometres they set up their winter home in sub-Himalayan Assam at about 300 m elevation.

Why do they make this unusual journey? Why don’t they winter in the terai closer to their breeding grounds? Do they breed in areas in Central Himalayas? In their 1983 epic Handbook of the Birds of India and Pakistan Salim Ali and Dillon Ripley have described the distribution of the Spot-winged Starling as “equivocal and imperfectly known”. Ornithologists haven’t added anything much beyond this and the status of this starling remains shrouded in mystery.

Have you seen this species? Where? Do add your sightings to the MigrantWatch database so that collectively we can better understand the migration of this odd species.

Here is the data page for Spot-winged Starling. At the time of writing, there were no records of this species in the database.