Black Kite lineatus: Intergrades in Northumberland
The recent spread of Black Kite northwards in Europe for breeding and in winter has been attributed in some quarters to the spread westwards of the West Siberia population, which is classified as an intergrade between Black-eared Kite Milvus migrans lineatus and the nominate form Milvus migrans migrans. See [Skyrpan, Mykola, Panter, Connor, Nachtigall, Winfried, Riols, Romain, Systad, Geir, Skrabal, Jan, Literák, Ivan, Kites Milvus migrans lineatus (Milvus migrans migrans/lineatus) are spreading west across Europe, Journal of Ornithology 162:317-323 April 2021].
As noted elsewhere Black Kite in Northumberland some of these Black Kite on the move find suitable habitat occupied only by Red Kite and have initially formed hybrid pairs with this species.
A blog by Guillermo Rodriguez Lazaro in Subalpine Birding Jan 15 2021, in ID Galleries on Eastern Black Kites in Europe: a new look, eastern-black-kites-in-europe-a-new-look, looked at the separation of migrans and lineatus in detail:
The separation of migrans and lineatus has been the focus of several papers (Forsman 2003, Lindholm & Forsten 2011, De Candido et al. 2013, Karyakin 2017), that described well the main differences between both taxa. In comparison to migrans, lineatus shows (in no particular order): 1. black ear-patch; 2. dark iris; 3. dull cere; 4. white on the primaries; 5. pale vent; 6. streaked body plumage; 7. brown head; 8. strong barring on inner primaries; 9. heavier structure; and 10. longer p5.
The photographs from my study area are often at moderate distance, in order to avoid disturbing nesting birds. But some are close enough to provide an insight into their genetics. Only breeding adults are considered, usually the only age-group present in spring. To boost the sample some late summer birds have also been considered as adults when the moult and context justify this assignment.
Photographs are from Tyne Green (24 Aug 2021) 1,
Bywell (19 July 2024) 6 7 8 9 ,
Towsbank (27 May 2024) 10 11 12 13.
All pictures show a dark iris, a dull cere and a brown head. In the field the structure appears distinctly heavy (compared to migrans) and the white on the primaries is a very striking feature. Therefore on 5 of the 10 counts, we have an indication that the colonisers of Northumberland are not migrans but a taxon resembling lineatus. Close-up photographs would help in assessing the remaining 5 features. It’s worth mentioning that the length of P5 has not been established as being particularly long, either from photographs or in the field, except on juveniles which are not considered reliable indicators for any taxon. Since we are looking for intergrades, rather than pure lineatus, we should not expect all of the 10 features to be found in any one bird.
Nick Rossiter
March 2026
