P6 Quick Fix 

This is the first in these series of a number of harrier hacks I will be uploading to aid the identification of the orange 1st winter harriers (Hen, Northern, Pallid and Montagu's Harriers) that are at times encountered whist birding in the UK and western Europe.

This isn't groundbreaking material but simply material I have both observed, read about and noted that I want to convey through the use of images, rather than a lengthy worded articles that are at times a little hard to process when trying to remember specific ID pointers in this Circus quartet.

I hope the following images provide birders with a quick reference tool to TRY (not always possible) and establish the identification of one of these mind blowingly beautiful birds if they happen to chance upon one.

Its all about primary 6!

With good photographs which are almost always taken these days head straight for the finer details of the harriers hand and isolate P6.

A lot can be said for this feather. Not only does it help you to take tricky individuals hopefully to species level but I believe it allows you to rule out hybrid phenotypes whereby Hen Harrier genes have worked their way into the equation.

Below is a photo of a 1st Winter Hen Harrier (Circus cyaneus) hand - note the classic baseball glove feel, brought about by the 5 exposed fingers. In this species P6 sits very proud and projects well beyond the rest of the neighboring inner primaries (P5 & P4). This is my 1st port of call when assessing ringtails nowadays given the amount of  Pallid Harrier (Circus macrourus) genes in circulation in western Europe. Structure of the hands in Northern Harrier (Circus hudsonius) are almost identical to cyaneus, unlike macrourus that should show a P6 that hugs the trailing edge of the rest of the wing (just a little longer than neighboring P5). Yes at times this feather can look a little proud in macrourus but never to the extent of cyaneus or a hybrid cyaneus x macrourus.

The pic below shows the prominent notch (inner web emargination) on P7 shown in cyaneus which is not shown in macrourus or pygargus. This feature CAN be seen on good photos of harriers underwings so just keep taking pics until you clinch it!.... If you look you will find it

Photo copyright Natural History Museum, Tring (courtesy of NHM, Tring Staff)

This pic (below) shows  P6 in the same cyaneus showing the obvious emargination that is not shown in macrourus or pygargus. This feather also shows a subtle notch on the inner web that is a lot less acute than the notch shown in P7 but a lot more evident than the non-existent notches of P6 of macrourus or pygargus. Personal observations show that P6 in hybrid cyaneus x macrourus hybrids show an emarginated outer web to P6.

Photo copyright Natural History Museum, Tring (courtesy of NHM, Tring Staff)

The three annotated pictures below were taken from the excellent book compiled by Marian Cieslak & Boleslaw Dul called Feathers Identification for Bird Conservation. Although they do not show feathers relating to the same age and sex of each of the species they are extremely valuable images in showing how the shapes of the feathers differ on an inter-specific level. I have included hudsonius as well (not annotated with black background) which was taken from The Feather Atlas in order to show how similar the wing formula is to cyaneus. 

This is  a quick sketch to illustrate the points mentioned. Although it is a rough drawing it is a lot easier to see in an image

TE=Trailing Edge

Trailing edge isn't entirely accurate I know but is to show how proud P6 is in cyaneus

Another quick reference I thought I would piece together is this feather table which highlights the feather properties per each species and hybrids.


I Love this subject! Much more research is needed into 1st generation hybrids and subsequent generation hybrid harriers and the study of hybrid wing formulas. These are early studies which I hope to pursue further in the future.

Hybrid harriers (be it macrourus x cyaneus OR macrourus x pygargus (former a lot more so)) are a very real issue and are only going to increase in years to come. Numbers of macrourus are pushing through the Mediterranean each spring in ever increasing numbers. This coupled with birds occupying breeding territories (double figures) in western Europe will only further exacerbate the frequency of these hybrids. These fired up macros and their offspring will continue to display to cyaneus further increasing the harrier mash up! I cant wait to see some of the results.

If you look at wing shape in ringtail harriers then you can see the reason for wing formulas being the way they are, given respective weights and migratory distances achieved by each species. Unless these western born "pure" macros are undergoing a super-fast evolution, to accommodate for western expansion and possible shorter migratory distances into Africa which is HUGELY unlikely then these anomalous wing formulas must be due to hybrid influence. That is unless we don't know enough about clinal variation in macro wing formulas across the entire western breeding range of this species. You only have to look at Chiffchaffs and how there wing formulas vary vastly throughout their distribution. Unfortunately the most likely reason is hybridisation which is something we as birders have to address. Another classic example are Caspian Gulls, how much Casp in a Casp defines a Casp? So when is a Pallid a Pallid and when is it a hybrid?

Imagine a cyaneus x macrourus hybrid breeding with cyaneus offspring that goes on to breed with pygargus.............aka a headwrecking hybrid!

Also if anyone who reads this is lucky enough to know of or has photos of macro x pygargus 
I would love to see them.


Thanks for your time