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Nuthatch Empire

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A Eurasian nuthatch of the western European subspecies (Sitta europaea caesia), encountered in southern England. Photo by Darren Naish.

Today I’d like to focus on passerine birds again, and this time on a group that I don’t think I’ve ever blogged about before: the certhioids. Scrap that. This article ended up being devoted entirely to just one lineage within Certhioidea: the nuthatches, or sittids (properly Sittidae). We start with the image above, taken in an English woodland here in Southampton, showing a Eurasian or Common or Wood nuthatch Sitta europaea. The Eurasian nuthatch is a mid-sized member of the nuthatch family, and by far the most widespread: it occurs from western Europe all the way east to Japan, also inhabiting parts of Morocco, various parts of the Middle East, and then eastern China, North and South Korea, and Taiwan.

Eurasian nuthatch of the S. e. caesia subspecies, photographed in Poland. Photo by Pawel Kunziar CC BY-SA 3.0.

As is the norm for birds that have ranges this extensive, a large number of ‘subspecies’ have been named. About 22 are currently recognised, grouped into three ‘subspecies groups’ (the ‘caesia group’, ‘europaea group’ and ‘sinensis group’). As is also ‘the norm’ for polytypic assemblages of this sort, some of those ‘subspecies’ look (and sound) ‘distinct enough’ to quality as species in their own right, most notably the Siberian nuthatch S. e. arctica/S. arctica. Many European populations – those belonging to the ‘caesia group’ – have white cheeks and throats but are otherwise buff underneath and reddish around the vent. Meanwhile, races from Scandinavia and many parts of Asia (members of both the ‘europaea group’ and ‘sinensis group’) have far more white on their bellies and flanks, while other ‘sinensis group’ populations are extensively orange-buff ventrally and lack white almost entirely. [Adjacent photo by Pawel Kunźiar/Jojo].

The distribution of the Eurasian nuthatch in the UK is quite interesting in that it’s almost wholly absent from Scotland and is missing completely from Ireland. It has been spreading north over the past several decades, however, and first bred in Scotland in 1989 (Enokksson 1993). It’s thought that this spread is related to its increased use of bird tables. As is obvious given the fact that the bird has failed to even cross the Irish Sea, the Eurasian nuthatch is a very sedentary bird. Individuals move little during their lifetimes, pairs stick to the same territory year-round, and there appears to be no exchange between the birds of Britain and those of continental Europe. The Siberian nuthatch, however, is known to move westwards as far as Finland during severe winters.

A nuthatch montage. Top left: Pygmy nuthatch (photo by Jimfbleak CC BY-SA-3.0). Top right: Red-breasted nuthatch (photo by Snowmanradio CC BY-SA-3.0). Bottom: Western rock nuthatch (photo by Devonpike CC BY-SA-3.0).

S. europaea is one of about 28 Sitta species, the members of which occur across Europe, Asia, northern Africa and North America. Some authors have suggested that Sitta should be split up into four genera (Dickinson 2006). However, the taxa suggested to be deserving of their own genera (oddballs like the Beautiful nuthatch S. formosa and Blue nuthatch S. azurea) are – based on their position within a recent phylogeny (Pasquet et al. 2014) – deeply nested within Sittidae so, if they were given their own genera, a new taxonomy for the entire group would need to be devised. Of course, there are lots of old generic names that would be resurrected if that were to happen: Leptositta Buturlin, 1916 for the White-cheeked nuthatch S. leucopsis, Poecilositta Buturlin, 1916 for the Blue nuthatch, Cyanositta Buturlin, 1916 for the Velvet-fronted nuthatch S. frontalis and kin, Rupisitta Buturlin, 1907 for the rock nuthatches, and so on. [Adjacent photos by JimfbleakSnowmanradio and Devonpike.]

Krüper's nuthatch (S. kruperi), photographed on Lesbos, Greece. Photo by Mark S. Jobling CC BY-SA 3.0.

In western Europe, S. europaea is a familiar denizen of deciduous and mixed woodland but it’s more strongly associated with coniferous forests in northern Europe and Asia. In fact, many nuthatches are associated with conifers. Several species – the so-called rock nuthatches – frequent environments where large expanses of bare rock are important. Given the fact that rock nuthatches are, again, nested within the nuthatch radiation (Pasquet et al. 2014), it has to be assumed that the lineage concerned made the transition from tree-climbing to rock-climbing at some point in their history. As someone interested in form-function correlation and how claw morphology correlates with lifestyle (or doesn’t) (Birn-Jeffery et al. 2012), I wonder if the species concerned differ in claw morphology from other nuthatches. So far as I can tell this hasn’t been studied. Nuthatches have, incidentally, occasionally been used as examplar ‘tree-climbing birds’ in studies of claw curvature (e.g., Glen & Bennett 2007, Dececchi & Larsson 2012).

“Like a miniature woodpecker”

Nuthatches are something like miniature woodpeckers – well, passerines that convergently mimic woodpeckers, anyway. Nuthatches are, in fact, strikingly woodpecker-like in those details of cranial musculature associated with shock-absorption (Spring 1965) (specifically, the protractor muscles that attach to the interorbital septum are gigantic). They climb with their very robust legs and feet: they don’t have a specialised prop-like tail, as do woodpeckers and trunk-climbing passerines like woodcreepers and treecreepers. Amazingly, they actually move via short hops even when climbing on vertical substrates (Fujita et al. 2008) and are famously adept at ‘head downwards’ climbing. Nuthatches have a well-known habit of storing nuts, seeds and even snails and insects in cache sites that include cracks in tree bark, hollows beneath stones on the ground, or cavities in trees, soil or rock piles.

Dead tree used as some sort of storage or hammering site at Ystradfellte, Wales. So - is it nuthatches that do this, or woodpeckers? The broken hazelnut shell on the right suggests that a nuthatch was behind this. Photos by Darren Naish.

More tree damage caused by birds (this time in the New Forest, Hampshire). Again: nuthatches or woodpeckers? Photo by Darren Naish.

I’ve found several nut storage sites over the years and have always assumed that they were created by Great spotted woodpeckers Dendrocopos major. Am I right, or could they have been created by nuthatches? One of them was right next to a nuthatch’s regular singing spot (compelling circumstantial evidence), and… look at the photo below showing the Red-breasted nuthatch inspecting a small hole in a tree. Having mentioned woodpeckers, I should say that certain woodpecker and nuthatch species are mortal enemies, competing for the same nest cavities, and reacting aggressively to one another at feeding and nesting sites. The Great spotted woodpecker is also an apparently significant predator of nuthatch nestlings. Nuthatches use mud to reduce the size of the nest entrance, and this helps prevent woodpeckers from entering – and other predators like martens and squirrels, of course (Wesołowski & Rowiński 2004).

Woodpeckers and nuthatches: not exactly the best of friends. This re-enacted scene depicts a fight between a Great spotted woodpecker and a Eurasian nuthatch. Drawing by Darren Naish.

Incidentally, the fact that some woodpeckers and nuthatches are so similar in generalities of lifestyle and appearance raises interesting questions about their evolution and history of co-occurrence. Shouldn’t the presence of one of these groups have ‘prevented’ the evolution of the other? Evidently this didn’t happen, so it is that there’s enough ‘ecospace’ for everyone? Or are they mostly avoiding competition in some important way? Well, some studies have found a surprising amount of overlap in bill size, foraging ecology and diet between sympatric nuthatch and woodpecker species (Willson 1971). This wouldn’t happen if these were species invented for a speculative evolution project, ha ha (I kid, I kid).

Nuthatch facts: tool use, colonial nesting, ‘new’ species

Corsican nuthatch female (above) and male, illustrated by John G. Keulemans in 1885. Image in public domain.

As always with groups of animals, there are various interesting ecological and behavioural snippets that tend to get mentioned in every bit of relevant literature, and I’d be letting the side down if I didn’t mention them again. One interesting thing about nuthatches is that several of them are (relatively speaking) only recently discovered. The Corsican nuthatch S. whiteheadi – wholly endemic to Corsica – was discovered in 1883, quite a big deal for a bird endemic to Europe, and the Algerian or Kabylie nuthatch S. ledanti caused an ornithological sensation when discovered in 1975. Since its discovery, additional populations have been discovered (one in 1989 and two more in 1990), but all are in close proximity in north-eastern Algeria.

Also worth noting is that the Western rock nuthatch S. neumayer (of eastern Europe and the Middle East) and Eastern rock nuthatch S. tephronata (of the Middle East and central Asia) were only reliably distinguished in the places where they overlap in the 1920s. Since then, there’s been substantial interest in the idea that these two avoid competing via the evolution of distinct bill shapes and sizes – that is, that character displacement or competitive exclusion is in effect (Vaurie 1951). However, those different bill shapes might be nothing to do with displacement or competition at all but, rather, be reflective of a size cline present across the populations concerned (Grant 1972).

Ten additional ‘new’ nuthatches named during the 20th century from Iraq (S. kurdistanica Ticehurst, 1923), Azerbaijan (S. armeniaca Vorob’ev, 1934), Afghanistan (S. subcaeruleus Meinertzhagen, 1938) and Iran (including S. obscura Zarudnyj & Loudon, 1905 and S. plumbea Koelz, 1950) – this list is far from complete! – are now regarded as junior synonyms of either S. neumayer or S. tephronata (Mlíkovský 2007). There’s also the mystery concerning the Long-billed nuthatch S. longirostris – a species based on 18th century paintings produced in Calcutta and suggested variously to depict an extinct tropical Asian species or rock nuthatches from the Zagros Mountains.

Another Red-breasted nuthatch: compare the hole this bird is making (or using) with the ones shown above. Image by Walter Siegmund CC BY-SA 3.0.

The tiny, endemic ranges of some of the species mentioned here are typical for quite a few nuthatches. They seem to be relicts, clinging to small patches of coniferous woodland (often at altitude) and hemmed in by habitat loss. Not all nuthatches are like this though. The Red-breasted nuthatch S. canadensis is an irrupting species that occurs across much of North America, undertakes regular migrations and has even crossed the Atlantic on occasion. An individual that landed in Norfolk, England, in 1989 – and resulted in a mass invasion of twitchers – lived there for about seven months before disappearing in May 1990 (Aley & Aley 1995). [Adjacent photo by Walter Siegmund.]

The North American Brown-headed nuthatch S. pusilla is of special interest in being a regular tool-user. It uses a scale pulled from pine bark as a foraging tool allowing the removal of additional bark, sometimes carrying the tool with it as it moves from tree to tree. Also interesting is the colonial roosting habit of the highly social Pygmy nuthatch S. pygmaea: as many as 167 have been recorded packed together in the same tree cavity (Sydeman & Güntert 1983).

Ad Cameron's illustration of communal roosting in Eurasian wrens. The picture depicts a case in which 30-40 wrens huddled together in the mud nest of a House martin (Delichon urbicum). (c) Ad Cameron.

An interesting question is whether the birds cling to the sides of the cavity in such huddles, or whether they actually stand on top of one another. I favour the latter explanation as this is what nuthatches will do in captivity; it also appears impossible that they could fit into the cavities concerned unless they were literally packed against, and on top of, one another. Do birds ever suffocate or get crushed in such mass huddles? Knorr (1957) reported cases where, respectively, 9 and 13 dead Pygmy nuthatches were found together in the same roosting holes. These probably represent individuals that were crushed to death while packed in the cavity (though maybe some died for other reasons). You might have heard about similar roosting huddles reported for Eurasian wrens Troglodytes troglodytes. In one case, 63 birds were sleeping together in the same one nestbox.

The bit at the end about burning frustration

The aim of this article was to discuss nuthatches (and other sittids: the Salpornis spotted-creepers) within the context of the relevant passerine clade as a whole (Certhioidea), and to cover wallcreepers and treecreepers as well. Oh well, next time. Suffice to say for now that phylogeny indicates that Asia was the place where most of nuthatch evolution occurred (Pasquet et al. 2014). Also seems that I really need to get hold of Erik Matthysen’s 1998 book The Nuthatches. Hey, it’s my birthday soon… though I am kinda running out of book-space.

Small passerines are really, really hard to photograph if, that is, you own 'standard' photographic equipment. I've never really managed to get a good photo of a nuthatch. This one was foraging on an oak tree at Exbury Gardens, Hampshire. Photo by Darren Naish.

More passerines here in time. For previous Tet Zoo articles on passerines, see…

Refs – -

Aley, J. & Aley, R. 1995. Red-breasted nuthatch in Norfolk: new to Britain and Ireland. British Birds 883: 150-153.

Birn-Jeffery, A. V., Miller, C. E., Naish, D., Rayfield, E. J., Hone, D. W. E. 2012. Pedal claw curvature in birds, lizards and Mesozoic dinosaurs – complicated categories and compensating for mass-specific and phylogenetic control. PLoS ONE 7(12): e50555. doi:10.1371/journal.pone.0050555

Dececchi, T. A. & Larsson, H.C. E. 2011. Assessing arboreal adaptations of bird antecedents: testing the ecological setting of the origin of the avian flight stroke. PLoS ONE 6(8): e22292. e22292. doi:10.1371/journal.pone.0022292

Dickinson, E. C. 2006. Systematic notes on Asian birds. 62. A preliminary review of the Sittidae. Zoologische Mededelingen Leiden 80-5 (14), 225-240.

Enokksson, B. 1993. Nuthatch Sitta europaea. In Gibbons, D. W., Reid, J. B. & Chapman, R. A. (eds) The New Atlas of Breeding Birds. T & A D Poyser, London, pp. 376-377.

Fujita, M., Kawakami, K., Moriguchi, S. & Higuchi, H. 2008. Locomotion of the Eurasian nuthatch on vertical and horizontal substrates. Journal of Zoology 274, 357-366.

Glen, C. L. & Bennett, M. B. 2007. Foraging modes of Mesozoic birds and non-avian theropods. Current Biology 17, 911-912.

Grant, P. R. 1975. The classical case of character displacement. Evolutionary Biology 8, 237-337.

Knorr, O. A. 1957. Communal roosting of the Pygmy nuthatch. Condor 59, 398.

Mlíkovský, J. 2007. Type specimens and type localities of Rock Nuthatches of the Sitta neumayer species complex (Aves: Sittidae). Journal of the National Museum (Prague), Natural History Series 176, 91-115.

Pasquet, E., Barker, F. K., Martens, J., Tillier, A., Cruaud, C.  & Cibois, A. 2014. Evolution within the nuthatches (Sittidae: Aves, Passeriformes): molecular phylogeny, biogeography, and ecological perspectives. Journal für Ornithology 155, 755-765.

Spring, L. W. 1965. Climbing and pecking adaptations in some North American woodpeckers. Condor 67, 457-488.

Sydeman, W. J. & Güntert, M. 1983. Winter communal roosting in the Pygmy nuthatch. Paper presented at Snag Habitat Management Symposium. Northern Arizona University, Flagstaff, Arizona, June 7-9, 1983, pp. 121-124.

Vaurie, C. 1951. Adaptive differences between two sympatric species of nuthatches (Sitta). Proceedings of the International Ornithological Congress 10, 163-166.

Wesołowski, T. & Rowiński, P. 2004. Breeding behaviour of Nuthatch Sitta europaea in relation to natural hole attributes in a primeval forest: Capsule Nuthatches used holes with strong walls, typically in live trees with entrances reduced by plastering, and ‘oversized’ interiors filled with bark flakes. Bird Study 51, 143-155.

Willson, M. F. 1971. A note on foraging overlap in winter birds of deciduous woods. Condor 73, 480-481.

Darren Naish About the Author: Darren Naish is a science writer, technical editor and palaeozoologist (affiliated with the University of Southampton, UK). He mostly works on Cretaceous dinosaurs and pterosaurs but has an avid interest in all things tetrapod. His publications can be downloaded at darrennaish.wordpress.com. He has been blogging at Tetrapod Zoology since 2006. Check out the Tet Zoo podcast at tetzoo.com! Follow on Twitter @TetZoo.

The views expressed are those of the author and are not necessarily those of Scientific American.





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  1. 1. Tayo Bethel 7:47 pm 08/25/2014

    Dr. Naish:
    Great article, as usual. Would it be fair to say that nuthatches fill the same ecological space as do small tree squirrels and similar arboreal rodents?

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  2. 2. BilBy 11:00 pm 08/25/2014

    When I was a kid growing up in Kent, U.K., nuthatches were one of my ‘must see’ birds but I never saw them in the patch of woods that was my stomping ground. That wood was, however, full of woodpeckers: greens, great spotted, lesser spotted. This might explain their absence.

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  3. 3. Alex Kleine 11:45 pm 08/25/2014

    Is it appropriate for a gritty Woody the Woodpecker movie remake against the Nefarious Nuthatch titled: “Woody the Woodpecker: End of Days?”

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  4. 4. Dartian 3:48 am 08/26/2014

    “S. subcaeruleus Meinertzhagen, 1938

    Oh dear, a species named by Richard Meinertzhagen. I looked up Mlíkovský (2007) to see what he had to say about the validity of this nuthatch; he seems to think that it’s legit.

    the mystery concerning the Long-billed nuthatch S. longirostris – a species based on lost 18th century paintings produced in Calcutta

    Hm? According to that same source, Mlíkovský (2007), at least two of those paintings survive – and they are in the UK, no less (in the National Museums and Galleries on Merseyside, Liverpool, and in the Natural History Museum, Tring, respectively).

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  5. 5. naishd 4:25 am 08/26/2014

    Thanks for comments. Tayo (comment # 1): I suppose nuthatches do overlap with arboreal rodents somewhat.

    Bilby (comment # 2): interestingly, I never, ever saw nuthatches as a child, yet now I see (and hear) them all the time. I don’t think this is anything to do with them not being around when I was younger – rather, it’s because I’ve become better at knowing where to look, and at identifying them (and their vocalisations).

    Dartian (comment # 4): I thought the same thing when I saw Meinertzhagen’s name. And I obviously erred on the paintings being lost – I will edit the text. I think I saw that the specimens had perished and thought that this applied to the paintings.

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  6. 6. BrianL 5:42 am 08/26/2014

    I found it intriguing that such a sedentary species that’s poor at crossing seas as the Eurasian nuthatch colonised the Philippines. How did that happen?

    However, I looked up the species in Harrap & Quinn’s ‘Tits, Nuthatches & Treecreepers’ and it does not mention Eurasian nuthatches occurring in the Philippines. Is the book outdated in that aspect? (Oh, the joys of having a vast library on various geeky subjects on hand when at home!)

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  7. 7. naishd 5:58 am 08/26/2014

    BrianL: I have Harrap & Quinn (1996) too, and you’re right that they don’t show the Philippines as part of the Eurasian nuthatch’s range. So, I’m left wondering where I got that information from… I can’t remember, nor can I find it stated anywhere, so I think I made an error there, sorry.

    As for why those Eurasian nuthatches in far eastern Asia have apparently made over-sea crossings (to get to Taiwan… and Japan?) while those further west have not, (1) maybe the sedentary thing only applies to the western forms, or (2) maybe the eastern ones got to those islands during times of lowered sea level and terrestrial connection. I don’t have time to check the literature on east Asian biogeography and geomorphological history right now.

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  8. 8. Dartian 6:34 am 08/26/2014

    Darren
    maybe the sedentary thing only applies to the western forms

    As you note in passing in the main article, the Sitta europaea asiatica subspecies from NE Europe and NW Asia periodically undertakes migrations towards the west (presumably during times of food shortage in their normal breeding range). The Siberian subspecies Sitta europaea arctica (or, as some sources prefer, the full species Sitta arctica) also undertakes eruptive migrations from time to time (Red’kin & Konovalova, 2006). So yes, some Eurasian nuthatch populations are less sedantary than those in Western Europe. However, I don’t know to what extent migrating nuthatches are willing – or capable – to cross open water (the red-breasted nuthatch that reached the UK was surely ship-assisted, wasn’t it?).

    Reference:
    Red’kin, Y. & Konovalova, M. 2006. Systematic notes on Asian birds. 63. The eastern Asiatic races of Sitta europaea Linnaeus, 1758. Zoologische Mededelingen, Leiden 80, 241-261.

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  9. 9. Heteromeles 10:48 am 08/26/2014

    Fun article!

    I’m not sure what a “signing spot” is though. Is it a singing spot misspelled?

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  10. 10. TheologyGeology 10:55 am 08/26/2014

    It struck me while i was birding in Greece just how simular due to convergence Rock Nuthatches are to the Canyon Wrens here in the American Southwest in behavior, and, stranger yet, in their call notes. So similar in fact, that when I first heard one calling, I was exceedingly confused as to why on earth I was hearing an American species in Greece! It made me think that perhaps there are certain sound sets that carry better in certain habitats, though that has nothing to do with taxonomy.

    And speaking from experience, pygmy nuthatches are not only exceedingly social (I once encountered a flock of thirty of them one early fall afternoon), but are very, very noisy.

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  11. 11. Felix2 11:20 am 08/26/2014

    The passerine march on Tetzoo Domination continues! Seriously, though, nuthatches are wonderful little birds; they visit my feeder all the time. One question that I’ve never been able to find the answer to: In all bird books I know (only U.S. ones, that is), nuthatches are placed with parids. Am I missing something and are they closely related, or is it just arbitrary?

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  12. 12. naishd 11:27 am 08/26/2014

    Heteromeles (comment # 9): yes, it was a dumb typo, now corrected.

    Felix2: yes, more passerines :) You’re right that books mostly make out that nuthatches are close to parids (see previous tit-themed articles). Nuthatches are part of Certhioidea, a clade (close to Muscicapoidea) that also includes treecreepers and kin, and is some distance from parids and kin. Simplified cladogram here.

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  13. 13. John Harshman 3:11 pm 08/26/2014

    I’m thinking that if that cladogram is correct (and there’s fair evidence for it), then we should just fold them all into Sylvioidea.

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  14. 14. Shuhray 3:34 pm 08/26/2014

    No passerine! Give us temnospondyls!

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  15. 15. DavidMarjanovic 4:39 pm 08/26/2014

    As for why those Eurasian nuthatches in far eastern Asia have apparently made over-sea crossings (to get to Taiwan… and Japan?) while those further west have not, (1) maybe the sedentary thing only applies to the western forms, or (2) maybe the eastern ones got to those islands during times of lowered sea level and terrestrial connection. I don’t have time to check the literature on east Asian biogeography and geomorphological history right now.

    In ice ages, Taiwan is not an island, and the whole area is forested. In contrast, Ireland is completely under inland ice in glacial maxima, and by the time the forest spreads to the Irish Sea, that sea already exists again.

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  16. 16. CS Shelton 1:31 am 08/27/2014

    We have red-breasted nuthatches here and their shape and color reminds me a little of badgers. They are stocky little wedges, at least compared to the profile of the more conventional passerines I see.

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  17. 17. Dartian 3:46 am 08/27/2014

    Regarding the willingness of forest-living nuthatches to cross wide expanses of non-forested areas; I don’t have information about the Eurasian nuthatch, but Harris & Reed (2002) have collected such dispersal distance limit estimates for two North American species, the red-breasted nuthatch Sitta canadensis and the white-breasted nuthatch Sitta carolinensis. The threshold distance of the red-breasted nuthatch is about 50 meters, and that of the white-breasted nuthatch is about 150 meters. So it seems that at least some nuthatches are indeed highly reluctant to fly even over very short distances of open terrain. (This ‘psychological’ unwillingness to cross open spaces doesn’t, of course, necessarily mean that nuthatches are anatomically or physiologically incapabale of doing so. But it does lend support to the idea that the vagrant UK red-breasted nuthatch UK didn’t actually fly all the way across the Atlantic Ocean.)

    Reference:
    Harris, R.J. & Reed, J.M. 2002. Behavioral barriers to non-migratory movements of birds. Annales Zoologici Fennici 39, 275–290.

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  18. 18. vdinets 4:27 am 08/27/2014

    In the winter of 2012-2013 there was a major irruption of red-breasted nuthatches in Louisiana, unprecedented in historic times. They showed up even in small patches of trees on the Gulf Coast, separated from the nearest forest by miles upon miles of fields and marshes. The numbers were so high that local ornithologists got seriously worried about possible depletion of source populations up north. But, as far as I know (in part from my own observations), this species was at or above normal abundance levels up north in late 2013, so either most birds made it back safely, or the population is so huge that the departured didn’t make a dent in it.

    I am ashamed to have completely missed the Sitta arctica split. In addition to morphology, acoustics, and lack of hybridization, it is also supported by molecular data (ref. below). It’s nice to know that at least some recent splits are well-substantiated ;-)

    Zink RM, Drovetski SV, Rohwer S. 2006. Selective neutrality of mitochondrial ND2 sequences, phylogeography and species limits in Sitta europaea. Mol. Phyl. & Evol. 40(3):679-686.

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  19. 19. Dartian 5:27 am 08/27/2014

    Vlad:
    They showed up even in small patches of trees on the Gulf Coast, separated from the nearest forest by miles upon miles of fields and marshes.

    Interesting! As the topmost eBird map on this site shows, that winter red-breasted nuthatches showed up even on islands situated quite far away from the nearest mainland. And, amazingly, in the late fall of 2012 five red-breasted nuthatches were reported from Bermuda*! Apparently, there are times** when nuthatches behave in untypical ways and are able to overcome their aversion against crossing open spaces, including water.

    * However, in the case of the Bermudan birds, I don’t think that the possibility of human-assisted dispersal can be entirely ruled out, since at least one of the nuthatches was actually found aboard a ship and another in a city harbour.

    ** A terminology question: should we call these kinds of irregular long-distance movements of birds (and other animals) eruptions or irruptions? I’ve seen both words used, but they are not entirely synonymous, are they?

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  20. 20. naishd 5:45 am 08/27/2014

    ‘Eruptions’ vs ‘irruptions’… I always thought it was irruptions.

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  21. 21. Chabier G. 5:54 am 08/27/2014

    BilBy: When I was a kid, nuthatches were also a must see bird to me, I tried to find them in every tree patch in my little mountain village in NE Spain, I never saw one. Now it’s a commonly seen species in the same place. But I found them in the Pyrenees, for example,in the same years, then I think it was not a problem of search accuracy. My subjective impression is nuthatches have spread in recent years in the Iberian ranges, some other local ornithologists think the same. The curious thing is that Great Spotted Woodpeckers have increased a lot,too, and also Lesser Spotted Woodpeckers. Green Woodpeckers have decreased in the same period. The main factor is the massive expansion of poplars along abandoned orchards in the river sides, following rural exodus.

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  22. 22. vdinets 6:47 am 08/27/2014

    I think the difference between irruption and eruption is the same as between immigration and emigration. Depends on which side of the border you are on.

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  23. 23. Felix2 10:16 am 08/27/2014

    Thanks for the cladogram, Darren. As for eruption vs irruption, yes, vdinets, dictionary.com(not sure how trustworthy it is on zoological matters)describes an eruption as an “issuing forth” and and irruption as “a sudden influx.”

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  24. 24. naishd 10:53 am 08/27/2014

    Aaaand… 23 comments!

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  25. 25. David Kelly 3:20 pm 08/27/2014

    Yes European Nuthatch first bred in Scotland in 1989, but now is widespread throughout southern Scotland. Rather than being associated with birdtables most Scottish ornithologists seem to think that the distribution of nuthatches has followed the northwards movement of the 17°C July isotherm. So the Nuthatch seems to be an indicator like many insects, especially butterflies and odonata of warmer summers. In fact a lot of birds that were quintessentially English when I was growing up are moving northwards and Hobbies, Reed Warblers and Bearded Reedlings are all now Scottish breeding birds.

    However, there is a down side and we Scots may lose some of our “arctic-alpine” flora and fauna as well as the effects warming seas may be having on the internationally important colonies of seabirds.

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  26. 26. naishd 4:12 pm 08/27/2014

    Ah, thanks, David – I did think about changing temperatures in the context of nuthatch spread but opted to go for ‘textbook wisdom’.

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  27. 27. Zoovolunteer 4:13 pm 08/27/2014

    You mention that they are absent from Ireland today, but is it not quite possible that they became extinct as a result of deforestation? Great Spotted Woodpeckers were absent as breeding birds until only the last few years, but there are apparently remains from the Bronze Age which suggests that they were once more a regular part of the fauna.

    Link to this
  28. 28. Heteromeles 4:25 pm 08/27/2014

    Harkening back to a previous post, I believe (working from memory), there’s a record of a flock of bushtits briefly visiting Catalina Island, and that it either came and/or returned to the mainland on a ship. It wasn’t exactly carted aboard by humans, but they followed the ship and clung to the rigging when tired.

    I’m not sure what you call this type of transportation, but it might explain how a nuthatch could get to Bermuda.

    Link to this
  29. 29. naishd 4:47 pm 08/27/2014

    Thanks for continuing comments. Zoovolunteer (comment # 27): the idea that the Eurasian nuthatch might have been present in Ireland at one time is possible but – as per comment # 15 – there might be reasons why they might never have occurred there. As it happens, this issue was considered in…

    Yalden, D. W. & Carthy, R. I. 2004. The archaeological record of birds in Britain and Ireland compared: extinctions or failures to arrive? Environmental Archaeology 9, 123-126.

    I haven’t been able to consult this (no access to the journal) – can anyone check what it says about nuthatches?

    Incidentally, I was sad to hear recently that Derek Yalden – a fantastic and fascinating man who I spoke to and corresponded with on many occasions – died relatively recently; I think in 2013.

    Link to this
  30. 30. DavidMarjanovic 6:25 am 08/28/2014

    A terminology question: should we call these kinds of irregular long-distance movements of birds (and other animals) eruptions or irruptions? I’ve seen both words used, but they are not entirely synonymous, are they?

    vdinets is of course right: they’re opposites from different points of view. An eruption is a break-out, an irruption (you know, in-ruption) is a break-in. A volcanic eruption is an outbreak.

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  31. 31. Jerzy v. 3.0. 6:29 am 08/28/2014

    I think spread of Nuthatches in Britain may be more related to re-forestation and maturing of forests and parks. They breed in pretty cold climates in Europe.

    The same is that many birds of tundra and cold wetlands in Europe likely spread far southwards historically because of deforestation, overgrazing producing tundra-like habitats and historical persecution of small carnivores and birds of prey.

    A digression, one nuthatch, Algerian Nuthatch, is perhaps most awkward bird to see in Western Palearctic. Its breeding range is not politically safe, and Algerian government prohibits bringing binoculars to the country.

    Link to this
  32. 32. Felix2 11:12 am 08/28/2014

    Global warming has had obvious effects on fist species, so to me linking the spread of nuthatches to rising temperatures doesn’t seem unwarranted. But I agree that reforestation was probably a factor too.

    Link to this
  33. 33. Felix2 11:13 am 08/28/2014

    FISH species, FISH species!!

    Link to this
  34. 34. Yodelling Cyclist 12:55 pm 08/28/2014

    WE DO NOT USE THAT WORD!

    ( ;-) )

    Link to this
  35. 35. John Harshman 12:59 pm 08/28/2014

    Now, now. Let’s remember, as Neil Shubin has pointed out, that tetrapods are just a specialized clade of fish, just as insects are a specialized clade of crustaceans and pulmonates are a specialized clade of snails.

    Link to this
  36. 36. Yodelling Cyclist 1:06 pm 08/28/2014

    Absolutely true. F**h are still taboo here, though.

    Link to this
  37. 37. naishd 1:25 pm 08/28/2014

    When this book is finished — working title The Vertebrate Fossil Record — you’ll see why I hate fish so much…

    Link to this
  38. 38. Yodelling Cyclist 2:26 pm 08/28/2014

    Why is this monster not being released in volumes?

    Link to this
  39. 39. Heteromeles 2:41 pm 08/28/2014

    Or, if you wanted to be cruel, you could release each chapter of The Vertebrate Fossil Record as a stand-alone, 99 cent book online from the Ol’ BigMuddyRiver. Then you could release the bound version for 10% less than buying all the chapters online, with an attached index to boot.

    Link to this
  40. 40. David Kelly 2:54 am 08/29/2014

    “I think spread of Nuthatches in Britain may be more related to re-forestation and maturing of forests and parks. They breed in pretty cold climates in Europe.

    The same is that many birds of tundra and cold wetlands in Europe likely spread far southwards historically because of deforestation, overgrazing producing tundra-like habitats and historical persecution of small carnivores and birds of prey.”

    Reafforestation certainly accounted for the spread of the Great Spotted Woodpecker and Eurasian Woodcock northwards into Scotland in the 19th and early 20th Centuries. The Nuthatch colonisation in northern Britain is most likely related to a warming of the climate, whether it is milder winters or warmer summers. Link

    David

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  41. 41. BrianL 6:41 am 08/29/2014

    @David Kelly:
    Could you please give some examples of such tundra specialists spreading far southwards in historical times?

    I also read that many species associated with the western European countryside were originally denizens of more open habitats in southeast Europe and the Middle East that spread as cultivated areas did and forests were hewn down. Examples would include Little Owl, Barn Owl, House Sparrow, Quail and Partridge. Is this correct?

    In the same vein, is it correct that, in Europe, the likes of swifts and jackdaws were originally mountain specialists that adapted to lowland cities as artificial habitats, like gulls and Rock Pigeon came to utilise cities as surrogate rockcoasts?

    Link to this
  42. 42. BrianL 6:45 am 08/29/2014

    ‘Rockcoasts’ should of course have been ‘cliffs’. Stupid neerlandisms.

    Link to this
  43. 43. Jerzy v. 3.0. 11:03 am 08/29/2014

    “Could you please give some examples of such tundra specialists spreading far southwards in historical times?”

    I am not David, but in Britain eg. Red Grouse, many waders, Twite, Merlin. Yes, many other birds of the open country are historically steppe or southern species.

    @Eurasian Nuthatch, forests and climate – look at the species range in Scandinavia and Siberia, and it is coping with much colder summers and winters than in Scotland. Perhaps a trap of investigatin British situation in isolation from other European countries?

    Link to this
  44. 44. Felix2 12:22 pm 08/29/2014

    Sorry for using *the word* ;) -the, erm, nontetrapod vertebrates. BrianL, the most commonly quoted example of birds adapting to cities because of their “cliffiness” is the peregrine. I would have thought swifts were originally lowland birds since they catch insects in flight (and insects(well, mosquitoes and midges) breed in bogs, and bogs are low altitude habitats). On the note of range expansion, American Opossums spread west, into more open areas, during human expansion. If an arboreal species can survive due to humans in prairie and chaparral, I don’t think generalist birds like corvids and columbids would need a city to be similar to their habitat to settle there.

    Link to this
  45. 45. vdinets 1:20 pm 08/29/2014

    Well, Scandinavia and Siberia are colder than Scotland on average, but summer temperatures might well be higher, at least in forested parts.

    Link to this
  46. 46. David Kelly 4:26 pm 08/29/2014

    @BrianL

    Snow Bunting, Rock Ptarmigan, Eurasian Dotterel, Dunlin, European Golden Plover, Common Greenshank, Common Scoter, Red-throated Diver………………….

    @vdinets

    The subspecies of Eurasian Nuthatch in Scandinavia and (and possibly species )in Siberia are not the same as that of Britain and so may be more adapted to those climates than that which occurs in Britain.

    David

    Link to this
  47. 47. Felix2 11:08 am 08/30/2014

    Uh-oh. As soon as we start talking about subspecies and species we’ll get to cladistics, and the mess of what is to be a species…oh, brother, take a drink ;) .

    Link to this
  48. 48. DavidMarjanovic 12:18 pm 08/30/2014

    is it correct that, in Europe, the likes of swifts and jackdaws were originally mountain specialists

    Jackdaws are still mountain specialists in mainland Europe. Britain is weird.

    Link to this
  49. 49. Lars Dietz 12:30 pm 08/30/2014

    Jackdaws seem to be quite common in the Lower Rhine region, so they’re certainly not mountain specialists everywhere in continental Europe. In fact, they don’t occur in high mountainous regions that are too cold for them.

    Link to this
  50. 50. CS Shelton 2:27 pm 08/30/2014

    On nuthatches, I’ve seen some birds in the last few weeks in unusual places. One was a nuthatch feeding off the ground. Normally I only see them on tree trunks, occasionally smaller limbs, and at feeders. Anyhow, this red-breasted nuthatch climbed down a twig until it was nearly on the ground and reached down. I was amused.

    The other one was a black-capped chickadee clinging to a swamp reed. I’ve never seen that before. I thought it looked a little too large to be a chickadee, but there’s just nothing else around here with markings even close – near as I can tell – and scale can be tricky at a distance.

    Link to this
  51. 51. BrianL 3:29 pm 08/30/2014

    @David Marjanovic:
    I’m rather surprised by that bold assertion of yours there too. Over here in the Netherlands, jackdaws are ubiquitous and very numerous inhabitants of all areas urban and cultivated. Landscapes really do not come much flatter than in the Netherlands. Perhaps your local jackdaws (or the ones that should be your local jackdaws but aren’t) are the weird ones? :)

    Link to this
  52. 52. MarcoTedesco 6:43 pm 08/30/2014

    Jackdaws are common at sea level here in Sicily, too.

    Link to this
  53. 53. Felix2 11:24 pm 08/30/2014

    Jackdaws…note that there are two species, whose ranges overlap in eastern Europe (I don’t know about the difference in their habitat preferences). I don’t recall ever hearing anything about them being mountain specialists, but I don’t know much about European birds (or most outside of California and New York states, for that matter-my ornithology is scant and biased towards hawks, falcons, etc.).

    Link to this
  54. 54. vdinets 2:39 am 08/31/2014

    Of course, today jackdaws occur all over Europe, but nine time out of ten they nest in buildings, old factory smokestacks, and other human-made structures. The question is, what was their range and preferred habitat before humans modified all European landscapes and provided nesting sites?

    I’ve been interested in this question for a while, and took notice of all jackdaw nests I saw in natural settings. They nest in cliffs (not necessarily rocky, but also sandy), rocky outcrops, and sometimes large tree hollows, but the latter are used by isolated pairs that don’t form colonies. They seem to be very rare or absent in large flat areas without human settlements. I strongly suspect (but am not sure) that without humans, they wouldn’t be able to colonize many parts of their present range after the glacial.

    Link to this
  55. 55. DavidMarjanovic 6:22 am 09/1/2014

    Wikipedia has a map that shows them covering the continent. The only jackdaws I’ve ever seen, though, were in the Alps and in Scotland.

    I might have mistaken some for eastern carrion crows, but jackdaws are smaller and have much smaller beaks that look downright weird to me. “Hey, crow, you’re doing it wrong!”

    Link to this

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