Monday, 21 August 2017

Tree Pipits come to the fore

The last couple of days have seen a marked increase in the number of Tree Pipits on the move at Billinge with a minimum of 10 recorded yesterday and 30+ today. It is not easy to keep track of numbers when you are busy ringing and it doesn't help that many don't call when flying over so I am sure I will have missed a few on both days. The increase in numbers on the move was also reflected in the ringing totals with 5 ringed yesterday and another 12 today.

Today's total of 12 ringed is the 2nd highest day total for the site and has only been bettered twice; on 14/08/14 and 17/08/15 with 13 ringed on both of those dates. Half of today's Tree Pipits were adults which is quite unusual but it gave me an opportunity to photograph some of the plumage features used when ageing birds in autumn. More information on ageing Tree Pipits can be found here, here and here (the latter being the best in my opinion) They are fairly straightforward to age once you get your eye in and fully understand their moult, especially if you get to handle quite a few, but I would say they are not as easy to age as Meadow Pipits.

S881408 1cy Tree Pipit. The fringes of the unmoulted median and greater coverts are quite worn and very pale (a cold bleached straw colour) when compared with those of the adult below and is probably from an early brood. It should be noted that the margins of median coverts and greater coverts of juveniles from later brood are less worn and can be more olive-buff like adults.

S881401 Adult (2cy+) Tree Pipit. Adults have fresher and more olive-buff fringed median and greater coverts.

S881401 2cy+ Tree Pipit. This adult was interesting in that it hadn't replaced 2 lesser coverts which stand out as being very worn and bleached.

S881401 2cy Tree Pipit. A closer look at those retained lesser coverts. They are very worn and have a narrow and bleached white fringe and shouldn't be mistaken for retained juvenile feathers. Birds like this can easily trap the inexperienced and unwary.

S881401 2cy+ Tree Pipit tail. Fresher and generally more pointed than the typical juvenile tail except for the central pair which are usually a bit more rounded when fresh compared to the central pair of a worn juvenile (see tail of S881408 below) but be aware some juveniles replace the central pair of tail feathers.

S881408 1cy Tree Pipit wing. This bird hasn't replaced any of the median coverts, greater coverts or tertials so there are no obvious moult limits to make ageing easy. Even the outer row of lesser coverts are all old. You just have to rely on wear and colour with birds like this.

S881408 1cy Tree Pipit tail

S881410 2cy+ Tree Pipit tail.

S881410 2cy+ Tree Pipit wing.

Ringing totals for 20/08/17 were: Sparrowhawk 1; Goldcrest 3; Blue Tit 9; Chiffchaff 6; Willow Warbler 15 (1); Blackcap 1; Whitethroat 2; Treecreeper 1; Wren 1; Tree Pipit 5; Chaffinch 1; Linnet 2; Goldfinch 2.

Ringing totals for 21/08/17 were: Chiffchaff 2 (1); Willow Warbler 6 (1); Whitethroat 1; Nuthatch 1; Tree Pipit 12; Chaffinch 4; Bullfinch 2.

Juvenile male Sparrowhawk 20/08/17
Juvenile male Sparrowhawk 20/08/17

Nuthatch 21/08/17

No comments:

Post a Comment