Isabelline Shrike (BBRC)

Isabelline Shrike, Lanius isabellinus.

Vagrant. Central Asia.

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IsabellineShrike 131003 DonnaNook MJTarrant topaz enhanceIsabellineShrike 201013 Donna Nook MJTarrant topaz enhanceDaurianShrike 201013 Pyes Hall GPCatley
 
Isabelline (Daurian) Shrikes : left, 1CY at Donna Nook October 10th 2003 (Michael Tarrant); centre (Michael Tarrant) and right (Graham Catley), 1CY Donna Nook October 20th 2013.
(Both individuals are of the nominate race L. i. isabellinus)
 
 
The taxonomy of the ‘red-tailed’ shrikes is far from settled and much debate continues. In January 2018, BOURC adopted IOC taxonomy and the Isabelline Shrike group was split into  Daurian (Isabelline) Shrike, Lanius isabellinus (polytypic) and Turkestan (Red-tailed ) Shrike, L. phoenicuroides (monotypic at present).

The BBRC advice in their 2018  report (British Birds 112: 556-626) is that adults of the two taxa, especially males, can be rather distinctive but 1CY birds, which form the bulk of British records, are on current knowledge not safely assigned to one species or another in a vagrant context. Note that five of the six Lincolnshire birds were 1CY individuals. The 1982 record has been especially contentious and after a review by BBRC of Isabelline/Red-tailed Shrikes (Stoddart and Hudson, 2021) this, along with 105 others, 1950-2019 were adjudged to be best left as 'Daurian/Turkestan' Shrikes.

DNA analysis may not always confirm identification and although most British examples are more likely to be isabellinus the BBRC approach is followed here with notes on whether particular individuals showed characteristics of either species. The natural desire to pin down a bird to one species or another is frustrated by this group of birds which exhibit a particularly fluid taxonomy. The six county records have been as follows:

 

Site First date Last date Count Notes
 Donna Nook 28/10/1978 30/10/1978 1  1CY, trapped, race indeterminate.
 Anderby Creek 07/11/1982 08/11/1982 1  Ad male.
 Gibraltar Point 15/11/1982   1  Same as Anderby Creek bird, November 7th and 8th.
 Pye's Hall, Donna Nook 14/10/1990 15/10/1990 1  1CY, a pale bird most reminiscent of isabellinus.
 Stonebridge, Donna Nook 13/10/2003   1  1CY, showing most similarity to phoenicuroides.
 Gibraltar Point NNR 10/10/2010   1  1CY, a pale most reminiscent of isabellinus.
 Pye's Hall, Donna Nook 20/10/2013   1  1CY, a pale bird most reminiscent of isabellinus
 
 
The red-tailed shrike seen at Anderby Creek and Gibraltar Point in 1982 most resembled phoenicuroides, although the race speculigerus was also mooted at the time but this has since become synonymous with isabellinus and is no longer used. Currently, it remains 'Daurian/Turkestan Shrike'.
 
RedTailedShrike November1982 AnderbyCreek GPCatley
 
 
The adult male "red-tailed" shrike, Anderby Creek, November 1982 (illustration by Graham Catley) - Isabelline or Red-tailed ?
 

 Finder’s report: Isabelline Shrike at Donna Nook, October 28th ,1978: first county record.

by S. Lorand.

Note:  this account is taken from the original Rarities Committee submission

 

Circumstances

At 13.00 hr. on October 28th C. Morrison (CM) inspected one of his mist-nets in the copse at Donna Nook, where he found a shrike whose identity he was unsure of. He put the bird into a bag and drove round to my (SL) house which is only a few minutes away. I was just preparing to leave for the dunes, but I examined the bird in the house and was able to identify it as an Isabelline Shrike. I telephoned other observers, but all were unavailable except for Dick Lorand who came round immediately. I made the following description.

 

Description

Head – forehead creamy white, very finely barred dark brown. Crown warm orange-brown contrasting with warm sandy brown of nape and mantle. Broad creamy white supercilium through, over and behind the eye contrasting with line behind the eye which was fox brown with blackish streaks. Ear coverts creamy grey with slight darker mottling. Bill pale silver-pink, upper mandible tipped dark brown, lower tipped light brown.

Upperparts – mantle suffusing into pinkish-brown of rump, uppertail coverts slightly paler. Tail sandy orange, contrasting with paler back. Tips of tail feathers very worn and abraded, paler than rest of tail and trace of thin line of off-white on very outer edge of outermost feathers which were about 10 mm. shorter than the rest.

Underparts – chin and throat creamy white, breast more dirty, pale cream suffusing to white on belly and undertail coverts. Sides of breast creamy white with slight trace of medium crescentic markings. Also trace of similar markings on the flanks, but these were somewhat indistinct.

Wing - lesser coverts similar to mantle but with very slightly paler centres to feathers. Median coverts blackish-brown, broadly tipped rufous. Greater coverts not as dark as median with blackish-brown band separating creamy- white tips. Primary coverts dark brown, tipped cream with dark centre to end feathers. Primaries dark brown with conspicuous white bases on 4th to 10th, also on rest but less prominently. The width of this wing bar was c.10 mm., although the white continued beneath the coverts. Bases of 8th to 10th primaries slightly more creamy. Tips of 7th to 10th off white, all primaries noticeably edged whitish-orange. Secondaries same colour as primaries but more broadly edged orange-white with broad off-white tips. Tertials warm orange-buff, broadly edged whitish-buff. Wing linings off – white with primaries and secondaries darker.

Bare parts – legs blackish-brown, iris brown.

Biometrics – the bird was ringed by CM and measurements taken, which were wing 95 mm., bill 13 mm., tarsus 27 mm., tail 82 mm. Weight at 13.30 hr. 33 g. Third to fifth primaries emarginated.

Behaviour post-release – the bird was released in the dunes by a wire dump frequently favoured by shrikes in the past. It landed on the wire and perched there about 20 yd. away for about 30 seconds. In the field it looked even paler, both on the upperparts and underparts, while the tail seemed a brighter orange. The dark line behind the eye was discernible but hardly conspicuous, while the legs seemed more blue-grey. Eventually it flew off to reveal the conspicuous white wing bars and in flight it seemed very long-tailed. It dived into a patch of Buckthorn, and we left it for the rest of the day.

Other observers were informed that evening, and during the next two days it was watched and photographed by many people. It had set up a territory about ¼ mile south of the spot from where it was released. The area on the edge of the beach comprised Buckthorn, Marram Grass with patches of sand, and many Ragwort plants. It appeared to be quite unconcerned by the presence of observers and fed readily on the bare sand. Several times it was seen to eject pellets and one of these which was recovered revealed insect and beetle contents. It frequently perched on Ragwort for long periods and at times could be watched from ranges down to 10 ft.

P. Haywood, who saw the Isabelline Shrike on the south coast earlier in October was under the impression that it the Donna Nook bird appeared to be even paler on the mantle and back and whiter on the underparts.

 

IsabellineShrike1 281078 DonnaNook KAtkinIsabellineShrike2 281078 DonnaNook KAtkinIsabellineShrike3 281078 DonnaNook Unknown

 

1CY Isabelline Shrike October 28th, 1978 , Donna Nook (Left/centre Keith Atkin, right Graham Catley)

 

 

Reference

Catley, G.P. (1982). Accounts of Lincolnshire rarities: Isabelline Shrike Lanius isabellinus speculigerusLincolnshire Bird Report 1982, 54-55.

Stoddart, A., and Hudson, N. (2021). From the rarities committee’s files: BBRC and newly split species. British BIrds 114 (1): 8-17.
 

(Account as per new Birds of Lincolnshire (2021), included October 2022)

 
 

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