EASTERN BLACK REDSTART ID (BONUS MATERIAL)
Vincent van der Spek & Nicolas Martinez (2018, 2019)
- Free bonus material!
- More pics, of more individuals to further illustrate the Dutch Birding ID article
- Includes newly found hybrids not used for the analyses
Figure 1. Eastern Black Redstart, first calendar-year male, Terschelling, Friesland, 5 November 2016. The bird that started the whole thing.
Please note that this bonus material section is not a true article itself. There's no real logical order that leads to a conclusion. The information we gather here is meant to further illustrate our Dutch Birding article.
In Dutch Birding 40.3 our identification article on hybrid males (Western) Black x Common Redstart vs. phoenicuroides Eastern Black Redstart was published. Our conclusion is that based on new and old features, nearly all males can be identified without using the wing formula, that was described so well by Steijn (2005). Furthermore the article shows that there's very little overlap in their temporal distribution: when the Eastern Blacks arrive, hybrids seem to be very rare (and vice versa).
2. The bonus material
The article is quite compact. We however have loads of extra material. And space on a website is not as limited as in a magazine. And while lower quality shots can be very instructive,often they cannot be printed. The main focus here is to present extra photographic material: something I often long for when I read an article.
Furthermore our sample (links to pictures) is downloadable for those who are interested to either draw their own conclusions, or to check ours. If you have any comments on our findings whatsoever, please do not hesitate to let us know.
3. Download our sample info!
We analysed the plumages of 62 male hybrids. For the temporal distribution we analyses 65 male hybrids.
At the time these we all hybrids we were able to find, but since then we found quite a few more but so far, none of these birds seems to challenge our findings.
Download the dataset that we used for the article here. See for yourself if you agree with our findings!
All (accepted) European records of Eastern Black Redstarts were gathered by Łukasz Ławicki. These were published in a separate article in DB 40:3 (Ebels et al 2018).
4. Wing structure (how did it work it again?)
Since it's about plumage, the wing structure is not explained into detail in the article. For a longer explanation, see Stein (2005).
To freshen up: two features are important: the presence (and size) or absence of an emargination on p6 (often difficult to see in the field) and the visible part of p5 and p6 (numbered outside in).
Black Redstarts (incl. Eastern) have p6 emarginated, whereas Common doesn't. This feature is very variable in hybrids, but if absent, or very small, this is a good indication of hybrid origin.
Easier to see in good photographs are the visible parts of p5 and p6.
First of all in Common the wing tip is often formed by p4, whereas in Black this is p5. So if p4 forms the tip, this is implicates a hybrid origin. Now very roughly, in Common the visible part of p5 and p6 is more or less equally long (Figure 2). In all Black Redstarts however, the visible part of p6 is obviously longer, often twice (but even more is possible) as long as p5. See figure 3.
Hybrids take a middle position, with overlap. When reminiscent of Common, or generally too small for a(n Eastern) Black, this is a strong indication of hybrid origin. The primary spacing of all Dutch records (until spring 2018) can be found in table 1.
Figure 2. Common Redstart, second calendar-year male, Meijendel, Zuid-Holland, the Netherlands, 9 July 2017.
The primary spacing feature is indicated. Unlike in Black Redstart ssp, the wingtip in Common can be formed by the 4th primary. Note that the visible part of p5 is about as long (in this case: even a bit longer) as the visible part of p5. In all Black Redstarts there's much more visible of p6. In hybrids this is variable.
Figure 3. Eastern Black Redstart, first calendar-year male, Terschelling, Friesland, the Netherlands, 5 November 2016.
The primary spacing feature is indicated. Note that the visible part of p6 is much longer than that of p5. The ratio is about 1: 1.7.
The circle indicates the moult limit within the greater coverts: the inner two (longer, with grey edges) are adult type feathers, the shorter, more buffy outer ones are still juvenile.
Table 1. Accepted records of Eastern Black Redstart in the Netherlands (up till April 2018), with nr of moulted greater coverts and measured primary spacing
In autumn, winter and spring, moult limits give away the age of young birds, both in Eastern Black and hybrids. It's often easiest to see within the greater coverts (Figure 3). Wing patches in hybrids vary (from absent to large, as in Western Black), but spring hybrids with large white patches will be adults rather than 2nd calendar year birds.
6.1 Additional photos: phoenicuroides
For an explanation per feature: see the DB article. The typical phoenicuroides features are highlighted in the pictures below.
Figure 4. Eastern Black Redstart, second calendar-year male, Barendrecht, Zuid-Holland, Netherlands, 14 January 2017 (Peter Soer). Same bird as plate 193 in the article (more good phoenicuroides features visible there).
Note following characters: A: no white wing panel; B: plan grey back; no rufous fringes on greater coverts; C: (very) little white on forehead; D: orange triangular shaped patch between blackish breast-patch and wing is solid feature of phoenicuroides males.
6.2 Additional photos: hybrids part 1
The pics below are additional photographs of hybrids that are also shown in the article.
Figure 5. Hybrid Common x Black Redstart, 2nd cy male, Leusden, the Netherlands, 14 April 2010 (Rutger Wilschut). Same bird as plate 196 in the article (more hybrid features visible there). Also see Figure 6.
The area within the triangle is grey (instead of orange) in this bird. Black or grey in this area is a diagnostic feature shown by half the hybrid males.
Figure 6. Hybrid Black x Common Redstart, 2nd cy male, Leusden, the Netherlands, 14 April 2012 (Rutger Wilschut). Same bird as plate 196 in the article, and Figure 5 here.
Messy breast patch, isolated dark spots on the belly and white band that "splits" the belly into two parts are solid hybrid features.
Figure 7. Hybrid Common x Black Redstart, male, Hilchenbach, Nordrhein-Westfalen, Germany, 27 April 2012 (Michael Frede). Same bird as plate 195 in the article (more hybrid features visible there).
This bird is fairly easy to separate from Eastern Black Redstart phoenicuroides by combination of: A large white wing-panel; B fairly large white forehead-patch (though not outside range of phoenicuroides); C no orange triangular shaped patch (diagnostic).
Figure 8. Hybrid Common x Black Redstart, male, Baden-Württemberg, Germany, 31 March 2013 (Daniel Kratzer). Same bird as plate 197 in the article (more hybrid features visible there)
Note A very small breast patch, perhaps too small for phoenicuroides and B diagnostically large white band on the belly, even splitting the orange on the belly into two parts.
6.2 Additional photos: hybrids part 2
Photographs of the birds below were not included in the DB paper, but they were used for the analyses.
Figure 9. Hybrid Common x Black Redstart, male, Wenslingen, Switzerland, 1 June 2017 (Nicolas Martinez). Note large white forehead patch, as in Common Redstart.
Figure 10. Hybrid Common x Black Redstart, male, Wenslingen, Switzerland, 1 June 2017 (Nicolas Martinez). Same bird as Figure 9. Note very messy breast patch and isolated black spots on the belly.
Figure 11. Hybrid Common x Black Redstart, male, Teufen, Switzerland, 26 August 2017 (Levi Fitze).
Note A dark area within triangle; B very messy breast patch, C pale orange underparts and D large white band on belly. All these features point towards a hybrid origin.
Figure 12. Hybrid Common x Black Redstart, male, Switzerland, 23 March 2003 (Simon Birrer).
Note A very messy breast patch and isolated black spots on belly, B large white band even splitting belly into two orange parts.
6.2 Additional photos: hybrids part 3
Photographs of newly found (presumed) hybrids, that were not analysed in the paper.
Figure 12. Hybrid Common x Black Redstart, male, France, 29 March 2018. Bird mostly looks like Common Redstart (Antoine Salmon). Also see Figure 13.
Note A wing tip formed by p4; B only weak emargination on p6; C very pale underparts.
In this shot, a theoretical very pale and poorly marked Common (no white forehead) is even an option, but Figure 13 also shows a throat patch that seems to be too large for Common. Besides, the primary spacing ratio = 1: 1,33, which fits a hybrid.
Figure 13. Hybrid Common x Black Redstart, male, France, 29 March 2018. Bird mostly looks like Common Redstart (Antoine Salmon). Same birds as Figure 12.
Note A very pale underparts (shown by up to 10% of the hybrids); B large white band on the belly; C white undertail coverts. All these features (and the primary spacing) diagnostically rule out phoenicuroides.
Figure 14-16. Presumed hybrid Common x Black Redstart, male, Hilversum, the Netherlands, 9 April 2018. Bird mostly looks like Common Redstart (14-15: Buddy van Nieuwenhoven, 16: Iwan Vermeij).
A upperparts fit Black better than Common; B no white on forehead would be very unusual for Common in spring; C throat patch limited, as in Common; D pale underparts shown by 10% of the hybrids; E large white band all the way down to the undertail coverts matches Common.
At least to the ear, the bird sang like a Common (Buddy van Nieuwenhoven in litt). Note the wing structure fits Common, with a wing tip formed by p4, a 1:1 primary spacing ratio (p5:p6) and no emargination on p6. Very pale Common occasionally occur (see e.g. here), and so do spring birds that lack any white on the head (here). If anyone knows a certain Common that combines both of these features, I'd like to know. I now cannot diagnostically rule out a both poorly marked and pale Common with certainty.
Alas, features C-E diagnostically rule out phoenicuroides anyway.
Figure 17. Hybrid Common x Black Redstart, male, Stramproy, the Netherlands, 17 May 2017 (Ruud van Dongen).
This very interesting bird was brought to my attention by Fred Visscher. Observer Ruud van Dongen already noticed its mixed song (with elements of both species) and made a good recording (recommended, here) and the relatively pale colour.
Song and features A-B point towards hybrid origin, C-D rule out phoenicuroides.
Upperparts perhaps fit Black better than Common. Furthermore A no white forehead would be unusual for Common; B throat patch too large for Common (would perhaps fit a phoenicuroides with a smaller patch); C large pale belly, paler than orange on breast; D pale undertail coverts.
ADDED 22 JUNE 2018
photo sent by Martino Bianchi
Figure 18. Hybrid Common x Black Redstart, male, in Vrtoče, Drvar, Bosnia and Herzegovina, 31 May 2018 (Martino Bianchi)
Bird mostly looks like Common Redstart, but breast patch way too large. No pics from upperparts available. Large white belly and very pale undertail coverts diagnostically rule out phoenicuroides. Suggestion of large white forehead patch. Though certainly not out of range for phoenicuroides, breast patch edges quite messy.
Figure 18. Hybrid Common x Black Redstart, male, Linosa, Italy, 27 October 2019 (Ciro Amata)
Interesting bird with a lot of Black Redstart vibes! Orange underparts and undertail coverts could fit Eastern Black. Wing formula unfortunately not photographed. However white on belly seems extensive, reaching high on the belly. Breast patch is messy, not sharply defined and there's 'smudge' on the spot we'd like to see the orange trriangle. Underparts look mottled overall, not clean enough for phoenucuroides.
With two more hybrids this autumn, and two previous ones Linosa has a remarkable streak of five records within a short period of time. We believe they are intermediate distance migrants.
Well, enough for now, but if you have an interesting bird that you would like to add to this page, don't hesitate to contact me!
We thank all photographers: Ciro Amata, Martino Bianchi, Simon Birrer, Ruud van Dongen, Levi Fitze, Michael Frede, Daniel Kratzer, Buddy van Nieuwenhoven, Antoine Salmon, Peter Soer, Iwan Vermeij, Rutger Wilschut. Furthermore we thank Andrea Corso, Thor Olsen, Hugo Touzé and Fred Visscher for their help with finding interesting photographic material.