Notes on a Vagrant Blyth’s Pipit in Malaysia. Part 1 – Behaviour and Ageing

Background

A Blyth’s Pipit was identified at MalimNawar, Perak, on 28th January 2017. Subsequently, it was discovered to have been present from at least 2nd January, when it was photographed by Amar Singh HSS. At the time of writing, the bird is still present (most recently seen on 7th April). This is only the second record of the species for Malaysia.

Throughout its long stay, the bird has been remarkably faithful to one small area of roadside grass, and it has been rather tolerant toward the many photographers and birders who have come to see it. Throughout much of its stay it has been in pre-breeding moult, providing a rare opportunity to document the progress of moult in a single bird.

Behaviour and Habitat

Blyth’s Pipit habitat. The bird feeds in the longer stalky grass on the far side of the track, as well as in the shorter grass on the near side. © Ooi Beng Yean.

The bird has faithfully frequented a small area of roadside grass verge either side of a dirt track which runs through an area of mining ponds. The track is infrequently used by fish-farm workers and recreational fishermen and birders using motorbikes, cars and SUVs.

The Blyth’s Pipit appears to prefer foraging in grass populated by sparse low vegetation and taller stalks. Its common foraging technique in this habitat is to locate small prey items such as spiders and small bugs by eye and then catch them, often by jumping upwards to pluck them off tall stalks. Paddyfield Pipits and Eastern Yellow Wagtails have also been noted using this foraging method occasionally, but nowhere near as frequently and regularly as the Blyth’s Pipit.

Blyth’s Pipit foraging. 20 Feb 2017 (left and centre). 24 Feb 2017 (right). © Mike Kan

In shorter grass devoid of taller vegetation it feeds much like other pipits and wagtails. It often forages on or near water buffalo dung, and has been seen to take flies and small maggots from these.

Blyth’s Pipit with fly sp. 27 Feb 2017.

Blyth’s Pipit with earwig sp. 8 Feb 2017. © Ooi Beng Yean.

The bird uses the dirt track for dust-bathing (see this short video), and this also seems to represent a territorial boundary for a resident pair of Paddyfield Pipits. At the beginning of the Blyth’s Pipit’s stay, its presence was tolerated by the Paddyfield Pipit pair, but recently, skirmishes have been more frequent.

Blyth’s Pipit (rear) with a local Paddyfield Pipit. 20 Feb 2017.

The Blyth’s Pipit rarely calls unless in an altercation with a Paddyfield Pipit. Normally when flushed by people or dogs it flies off silently, flying a short distance, and then circling back to its preferred area shortly after the perceived threat has passed. When flushed it occasionally perches on telegraph wires or a fence post. It does not habitually bob the tail up and down like a wagtail, but occasionally flicks the tail downward rather deliberately.

What age?

Determining the age of pipits can be difficult! It all depends on the fine details of plumage and moult, particularly in the wings and tail.

There is a detailed summary of moult in pipits and wagtails in Alström and Mild’s Pipits and Wagtails of Europe, Asia and North America, which is available online as a pdf here (scroll down to page 24ff). It bears reading in full, but I will attempt a précis of the salient points here.

Juvenile plumage: The first proper plumage succeeding natal down. The feathers develop simultaneously so are uniformly fresh or worn.

Post juvenile moult: Begins 2-5 months after fledging. In all pipits except some Paddyfield Pipits, this is a partial moult. It includes the head and body feathers and a variable number of secondary coverts and tertials, sometimes also the central pair of tail feathers. Most lesser coverts, none to all median coverts, none to a few inner greater coverts and none to all tertials are renewed during the post-juvenile moult. Once post-juvenile moult is complete, the bird is in first winter plumage.

Pre-breeding moult: In the late winter or early spring of the second calendar year, i.e. when the bird is 9–10 months old, most pipits and wagtails go through a partial pre-breeding moult to obtain first-summer plumage. In most pipit species most of the head and body is moulted (a few feathers, particularly on the scapulars and rump, are often retained) as well as some to all median coverts, a few inner greater coverts (second innermost, 9th, usually replaced first), one to all tertials, and often the central two rectrices.

Post-breeding moult: At the age of a little over a year, after breeding, the first-summer  bird goes through a complete post-breeding moult, resulting in adult plumage, i.e. the final plumage.

The moults in adults follow the schedule and type of the young bird after the post-juvenile moult, i.e. a partial pre-breeding moult in late winter to early spring and a complete post-breeding moult which starts shortly after breeding. (The way I remember this is “Some in Spring; All in Autumn!”). The post-breeding moult usually commences either with the innermost primary or with some feathers on the head and body, often mantle feathers. The primaries are moulted descendantly (from the innermost outward), and the primary coverts are usually moulted in phase with their corresponding primaries. Soon after the moult of primaries has begun, that of rectrices and tertials begins. The tail moult commences with the central pair and normally continues centrifugally. The central tertial is usually shed first, approximately at the same time as the third primary, then usually the shortest and finally the longest. The secondary moult usually begins at about the same time as the sixth primary is shed, and proceeds ascendantly, starting with the innermost. However, the greater coverts tend to moult from the body outwards—thus not renewing in phase with their corresponding secondaries—but the sequence is often irregular, and sometimes most of them are renewed at much the same time. The median and lesser coverts are generally moulted rather irregularly, and most or all of the medians are often renewed simultaneously. The alula is generally replaced after the secondary coverts, usually in an irregular sequence. The outermost primary and innermost secondary get fully grown at approximately the same time, the latter often marginally later. The primaries, primary coverts and secondaries (but not necessarily the secondary coverts, tertials and alula) are as a rule moulted symmetrically across the wings. The head and body moult is usually completed around the same time as, or slightly before, the moult of the flight feathers, the head on average slightly later than the body.

The moult usually lasts 1–2 months, and is completed before the autumn migration.

Ageing

Most first-winter pipits show two generations of secondary coverts, often also tertials. Retained juvenile secondary coverts and tertials are more worn and, owing to bleaching, show paler tips/edges and marginally paler centres than newly moulted ones. Unmoulted juvenile secondary coverts are also usually slightly shorter than adjacent newly moulted ones. In several species (particularly the ‘large’ pipits) unmoulted juvenile secondary coverts and tertials are also differently patterned compared to newly moulted adult-type feathers. The resulting moult contrast (moult limit) is diagnostic for first-winter birds, as adults in the autumn show only one generation of secondary coverts and tertials (but see below).

It should, however, be noted that wear and bleaching is not uniform across the wing feathers, and this may result in the appearance of moult contrast. The inner primaries and outer secondaries are less exposed than the outer primaries and inner secondaries, and therefore less subject to wear and bleaching. The inner greater coverts, notably the 9th (second innermost) although not the usually concealed 10th, are more prone to wear and bleaching than the outer ones, and hence the outer greater coverts sometimes appear to be newer than the inners. The outermost three or so median coverts are less subject to bleaching and wear than the rest, and frequently look fresher than adjacent median coverts even when the same age. The tertials may become more worn than the secondary coverts.

It might be useful to do a quick review of the topography of the wing, courtesy of Beng Yean’s perfectly-timed photo below.

Blyth’s Pipit. 6 Feb 2017. © Ooi Beng Yean.

1. Marginal (secondary) coverts (sometimes lumped together with the lessers)
2. Lesser (secondary) coverts
3. Median (secondary) coverts
4. Greater (secondary) coverts
5. Alula
6. Primary coverts
7. Primaries
8. Secondaries
9. Tertials

The most important group of feathers in determining the age of this bird are the median coverts, as juvenile feathers are differently patterned from first winter and adult feathers (in Blyth’s Pipit).  In juveniles, the black centres of the median coverts follow the shape of the feather, whereas on first winters and older, they are more square-cut, as these are. See here for a juvenile. Juvenile-patterned median coverts can apparently be retained until ‘midwinter’ (see these pics taken on 30 December).

But is the bird in its first winter or is it older?

If this bird is a first winter, one would expect to see 1. Evenly aged remiges (primaries and secondaries) and 2. Possibly (though not always) some evidence of moult contrast due to their being two ages of e.g. coverts. 3. Possibly (though not always) the central pair of rectrices (tail feathers) being newer than the rest.

If it is an adult, one would expect to see 1. No moult contrast, though possibly some unevenness of bleaching, with the outer greater coverts and the outer median coverts being less bleached than the rest of the feathers in their respective feather tracts. 2. Perhaps some unevenness of wear in the remiges (with inner secondaries and inner primaries being more worn than the rest, because they were moulted earlier in the complete post-breeding moult). 3. The tail feathers being evenly aged.

In the photo above, we can see:

1 The primaries and secondaries appear uniformly aged.

2. No obvious moult contrast in the coverts.

So, honestly, I cannot age the bird from this photo!

Fortunately, the first photos taken of this bird were on 2 Jan – much earlier than this photo. Here’s one:

Blyth’s Pipit. 2 Jan 2017. © Amar Singh HSS.

A close look at the median coverts reveals something interesting!

Blyth’s Pipit. 2 Jan 2017. © Amar Singh HSS

The question is – is this differently-patterned feather a median covert or a lesser covert? Comparing it with the lesser coverts on the numbered photo, it seems more worn and to have a narrower pale fringe than those feathers, so I think it’s a median covert. Here’s another view:

Blyth’s Pipit. 2 Jan 2017. © Amar Singh HSS

I think the feather labelled 1. is a median covert, and the other labelled 2. is a lesser covert (with a buffier, broader fringe).

If I’m correct, and it is a median covert, then it is a juvenile covert, which ages this bird as a first winter (hatched in 2016). By the time Beng Yean’s photo was taken on 6 Feb, this feather had dropped out and been replaced by an adult-patterned covert.

I might be wrong – in which case, please let me know what you think. I did say that ageing pipits can be difficult!

In the next post, I will look in more detail at the progress of the pre-breeding moult in this bird.

My thanks to Amar Singh HSS, Mike Kan and Ooi Beng Yean for allowing me to reproduce their photos in this post.