Abstract A presumed hybrid Common Redstart Phoenicurus phoenicurus x Whinchat Saxicola rubetra was present at Grutness, Shetland, on 13th–22nd September 2021. There is only one confirmed case of such a hybrid that we know of, a bird trapped at Lista Bird Observatory in Norway in September 2013; this was also considered to be the first proven case of intergeneric hybridisation within the Muscicapidae. The Shetland bird is described here.

 

On the morning of 16th September 2021, PVH was birding at Grutness, Shetland, when he saw what he assumed to be a Common Redstart Phoenicurus phoenicurus fly across the road and dive into cover. After a brief wait, the bird was seen again on the top of a sowthistle Sonchus. Only its head and breast were in view but the pale throat, pale supercilium, brownish ear-coverts and indistinct spotting across the breast were at odds with Common Redstart and were much more like those of a Whinchat Saxicola rubetra or a species of stonechat. While he was trying to photograph the bird, it was flushed by a low-flying helicopter and lost to view.

Despite trawling through the memory banks, PVH could think of nothing that seemed to fit. At this point, he phoned RR then continued to search the area. He saw the bird again in flight and, although distant, this view helped to clarify the tail pattern. The central tail feathers and the distal third of each of the other tail feathers were blackish, creating a wheatear-like inverted T, and the rest of the tail and the rump were deep orange-red. 

RR soon arrived and, in due course, the bird became more settled along a fence line in a horse paddock. Following some discussion, which involved eliminating all the other possibilities that we could think of, the only solution appeared to be a Common Redstart x Whinchat hybrid. After posting news and photos of the bird on the Shetland Scarce Birds Whatsapp group, we received a link to photos of a known Common Redstart x Whinchat hybrid, at Lista Bird Observatory in Norway on 18th September 2013. This looked very similar to our bird. The Norwegian bird was trapped and confirmed by a DNA sample to be the offspring from a pairing of a male Common Redstart and a female Whinchat (Hogner et al. 2015; https://bit.ly/34UYQku). It was considered to be the first proven case of intergeneric hybridisation within the Muscicapidae. We are unaware of any other claims of putative hybrids between these species (although a bird photographed in Sweden in August 2021 was considered by the observers to be a hybrid between a Common Redstart and a Northern Wheatear Oenanthe oenanthehttps://artportalen.se/Image/3582418).

Later that day, both Anne Powell and Roger Thomason posted photographs of the Grutness bird on social media. These had been taken on 13th September but the bird’s identity not realised. The ‘Whinstart’, as it affectionately became known, remained at Grutness until at least 22nd September.

Description and behaviour
Essentially, the bird appeared Whinchat-like from the front and stonechat-like from behind, but with the rump and tail colour of a Common Redstart. Structurally, it was somewhat intermediate between a Common Redstart and a Whinchat, appearing slightly dumpier than the former. Its primary projection was long (almost the same length as the exposed tertials), within the range of Common Redstart but probably at the long end for a Whinchat. The tail appeared a little short for a Common Redstart but a little long for a Whinchat. The bill was slim and black, more akin to a Common Redstart, appearing longer and less heavy than that of a typical Whinchat.

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110. Presumed hybrid Common Redstart Phoenicurus phoenicurus x Whinchat Saxicola rubetra, Grutness, Shetland, September 2021. 

Roger Riddington

The head pattern was most similar to a Whinchat but with a more subdued supercilium. The brownish crown was streaked darker. Fairly distinct pale buff supercilia extended back beyond the ear-coverts and met in a pale bridge over the base of the bill. The supercilia were less distinct (more suffused with buff and some darker flecking) than those of a typical Whinchat. There was a reasonably distinct buffy-white orbital ring. The lores were dark and, along with a faint dark border to the upper ear-coverts, formed an indistinct dark eye-stripe. The ear-coverts were slightly mottled brown, much the same tone as the crown and nape. The chin and throat were whitish with the white of the chin extending back underneath the ear-coverts in typical Whinchat fashion. There was also a slight pale indent in the submoustachial area, as shown by Whinchat. 

There was an orange-buff wash to the sides of the breast (the intensity of this varying with the light and at times appearing simply warm buff). This wash was gradually lost on the lower breast, and this area, along with the flanks and the undertail, was whitish, although there was often an orange wash apparent on the rear flanks. The breast showed reasonably distinct mottling (spotting) as a result of dark feather centres, although the intensity of this spotting varied with the light and at times appeared much less distinct. This spotting also extended down the flanks. 

The brownish nape was faintly streaked darker, contrasting with the more heavily marked mantle and back. These upperpart feathers showed a pattern similar to that of a first-winter Whinchat, with a dark feather centre, a pale brownish-buff fringe and a white terminal spot, although the contrast between the dark area and pale area of the feather was less than in a typical Whinchat and the white tip smaller. This meant that from the rear, at least at any distance when fine detail could not be seen, the upperparts actually looked quite like those of a female or first-winter European Stonechat S. rubicola. The rump was a bright orange red with just a hint of darker feather centres on the central rump. 

The wings appeared dark blackish with a buff panel in the secondaries and pale buff fringes to many of the feathers. The primaries had whitish tips. The alula and primary coverts were blackish, the latter with narrow pale fringes. The median and greater coverts showed blackish centres with pale buff fringes, the inner two greater coverts with a paler, whitish tip. All the flight feathers were blackish; the tertials showed pale buff-white fringes, the secondaries a richer buff fringe – giving rise to the buff wing panel – and the primaries much narrower pale fringes and whitish tips.

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111. Presumed hybrid Common Redstart x Whinchat, Grutness, Shetland, September 2021. 

Ian Andrews

The tail looked dark in perched views as the central tail feathers appeared dark blackish, but when opened revealed a startling orange-red colour over the basal two-thirds and a blackish distal third, with pale tips to each feather. All but the central pair of feathers showed this pattern.

The legs were thin and black. The bird was not heard to call.

The bird behaved fairly typically for both migrant Common Redstart and migrant Whinchat in an open situation in Shetland. It would hop rapidly along the ground when feeding and regularly fly up onto a fence post or a rock for a few seconds before going back down to feed. It would also occasionally fly into dense cover, from where it would often perch on top of an umbellifer (Apiaceae) or sowthistle. Often, after alighting on a post or similar, the bird would pump its tail up and down in a relatively shallow movement three or four times in succession but it never quivered its tail in the manner of a Common Redstart.

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112. Presumed hybrid Common Redstart x Whinchat, Grutness, Shetland, September 2021. 

Ian Andrews

Photographs of the Norwegian hybrid show it to have looked remarkably similar to the Shetland bird and, although other plausible hybrid possibilities have been mooted for the Grutness bird (for example a Whinchat x Bluethroat Luscinia svecica or even a Stejneger’s Stonechat S. stejnegeri x ‘Caspian Stonechat’ S. maurus hemprichii), we believe that Common Redstart x Whinchat is the best fit. The head pattern and the pattern of the individual feathers of the mantle, back and scapulars are very close to those of a Whinchat, while the rump and tail colour point strongly to a Common Redstart. Sadly, we were unable to obtain a DNA sample from the bird.

Redstarts appear to be relatively promiscuous, producing among the most frequently recorded intrageneric passerine hybrids between clearly separated species. Martinez et al. (2019) reported a notable increase in hybrids within the genus Phoenicurus during the last 30 years. 

Hybridisation is believed to be more likely when populations of one (or both) of the parent species is decreasing; as we contemplate the catastrophic declines in many species at the current time, the occurrence of unexpected hybrids is perhaps something that birders in Europe should be increasingly alert to.

Acknowledgments
We thank Chris Batty, Pierre-André Crochet, Andrew Harrop, Josh Jones and Dan Pointon for invaluable input on that first morning; Jason Oliver for drawing our attention to the Norwegian hybrid and Richard White for a link to the Swedish hybrid; and Andrew Harrop for commenting on a draft of this article.

References

Hogner, S., Burgas Riera, A., Wold, M., Litfield, J. T., & Johnsen, A. 2015. Intergeneric hybridisation between Common Redstart Phoenicurus phoenicurus and Whinchat Saxicola rubetra revealed by molecular analyses. J. Ornithol. 156: 829–836.

Martinez, N., Nicolai, B., & van der Spek, V. 2019. Redstart hybrids in Europe and North Africa. Brit. Birds 112: 190–210.

 

Paul V. Harvey, Shetland Biological Records Centre, Shetland Amenity Trust, Lerwick, Shetland ZE1 0NY; e-mail[email protected]

Roger Riddington, Spindrift, Eastshore, Virkie, Shetland ZE3 9JS; e-mail [email protected]

Volume: 
Issue 3
Start Page: 
170
Authors: 
Paul V. Harvey and Roger Riddington
Display Image: 

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