Lefranc, N. & Worfolk, T. 1997. Shrikes: A Guide to the Shrikes of the World. Pica Press. Mountfield, Sussex.

Shrikes of the World | BTO - British Trust for Ornithology

Jobling, James A (2010). The Helm Dictionary of Scientific Bird Names. London: Christopher Helm. p. 219. ISBN 978-1-4081-2501-4. Rafinesque, Constantine Samuel (1815). Analyse de la nature ou, Tableau de l'univers et des corps organisés (in French). Palermo: Self-published. p.67.Shrike". Oxford English Dictionary (Onlineed.). Oxford University Press. (Subscription or participating institution membership required.) French, P.R. 2009. From the Rarities Committee’s files: Identification of Dark-breasted Barn Owl in Britain. British Birds 102: 494-503.

Shrikes of the World : Norbert Lefranc : 9781472933775 Shrikes of the World : Norbert Lefranc : 9781472933775

Golawski, A.; Mroz, E.; Golawska, S. (2020). "The function of food storing in shrikes: the importance of larders for the condition of females and during inclement weather". The European Zoological Journal. 87 (1): 282–293. doi: 10.1080/24750263.2020.1769208. ISSN 2475-0263. Olsson U., Alström P., Svensson L., Aliabadian M. & Sundberg P. 2010. The Lanius excubitor (Aves, Passeriformes) conundrum – Taxonomic dilemma when molecular and non-molecular data tell different stories. Molecular Phylogenetics and Evolution 55: 347-357.Merlin comprises nine subspecies, of which four are of most relevance here. In the Palearctic aesalon breeds across northern Europe to western Siberia, subaesalon in Iceland and pallidus (‘Steppe Merlin’) in northern Kazakhstan and south-west Siberia. In North America, nominate columbarius (‘Taiga Merlin’) breeds across the north of the continent. The splitting of Palearctic and Nearctic Merlins has been proposed. The taxonomy of the ‘Great Grey Shrikes’ is in a state of considerable flux and at least six potential species have been identified though not formally proposed (Olsson et al. 2010). Pending further work, IOC currently defines Great Grey Shrike as comprising twelve subspecies, of which ten inhabit North Africa, the Middle East and Central Asia and have been treated by many authors as ‘Southern Grey Shrike’. A further five North Asian and Nearctic taxa are treated by IOC as a separate species – ‘Northern Shrike’.

Shrikes of the World by Norbert Lefranc | Perlego [PDF] Shrikes of the World by Norbert Lefranc | Perlego

McCullough, J.M.; Hruska, J.P.; Oliveros, C.H.; Moyle, R.G.; Andersen, M.J. (2023). "Ultraconserved elements support the elevation of a new avian family, Eurocephalidae, the white-crowned shrikes". Ornithology. 140 (3): ukad025. doi: 10.1093/ornithology/ukad025. Common Swift comprises two subspecies – nominate apus across the Western Palearctic and northern Russia and pekinensis (‘Eastern Common Swift’) from Iran to Mongolia and northern China (Cramp et al. 1985). Their predatory habits, which will often see them take large insects or, in many cases, small birds or mammals only amplifies their uniqueness among passerines, while a penchant for choosing exposed perches from where to sit and survey their territories makes them generally easy to observe and study.Peregrine is widespread and exhibits considerable variation, with sixteen subspecies recognised worldwide. Nominate peregrinus breeds across Europe and northern Asia but is replaced across northernmost Arctic regions by calidus (‘Russian Peregrine’), a long distance migrant. Similarly, in North America the subspecies anatum is replaced in northernmost regions by tundrius (‘Tundra Peregrine’), also a long distance migrant. Crested Tit comprises seven subspecies, of which four are of possible relevance here. The subspecies scoticus occurs in north-central Scotland, nominate cristatus (‘Northern Crested Tit’) in Scandinavia, eastern Europe and Russia, mitratus (‘Central European Crested Tit’) in central and western Europe and abadiei in north-west France (Cramp et al. 1993). Sustaita, Diego; Rubega, Margaret A.; Farabaugh, Susan M. (2018). "Come on baby, let's do the twist: the kinematics of killing in loggerhead shrikes". Biology Letters. 14 (9). doi: 10.1098/rsbl.2018.0321. PMC 6170751. PMID 30185607. Willow Tit comprises fourteen subspecies but only three are of relevance here – kleinschmidti (‘British Willow Tit’) from Britain, borealis (‘Northern Willow Tit’) from Scandinavia, Denmark, the Baltic States, European Russia and Ukraine and rhenanus (‘Central European Willow Tit’) breeding on the near-continent east to westernmost Germany and north-west Switzerland.