Our paper is dubbed a Classic!

Google Scholar has released a new feature that lists “Classic Papers: Articles That Have Stood The Test of Time”. I am very pleased to see that a paper that I was happy to co-author with late Niclas Jonzén is among the classics, as the fourth most cited publication about birds published in 2006.

In 2005 I published my first ever peer reviewed paper, which was an analysis of long-term bird ringing data from Ottenby Bird Observatory. The 2006 Science paper was, in some sense, triggered or inspired by this work, and here we expanded and used bird ringing data several Scandinavian bird observatories, in combination with data from Capri in Italy. We could show that migratory birds that spend their winter south of the Sahara responded even more strongly to the European winter weather (which determines the progression of the following spring), than did short-distance migrants. So after a cold and dry winter, spring came later, and migratory birds arrived later.

We already knew that the birds arrived later at the Scandinavian breeding grounds, but in this paper, we made use of the data from Capri, as we argued that the arrival to Italy should reflect the departure from sub-Saharan Africa. The rationale for this is that there isn’t much opportunity to spend time between the two regions, as the birds have to cross two major barriers – the Sahara desert and the Mediterranean Sea. Furthermore, even after accounting for the winter weather, there was a clear trend over time towards earlier arrival, which we argued reflects natural selection for earlier spring migration.

Read the classic paper, the preceding Ottenby paper, or check out Google Scholar’s top list for bird papers.

The enigmatic São Tomé grosbeak is a giant seedeater

We have finally published the first piece of the puzzle about the critically endangered São Tomé grosbeak Neospiza concolor in the ornithological journal Ibis. So what is special about the São Tomé grosbeak? Pretty much everything:

  • It is among the rarest species on Earth
  • It was not seen for over 100 years
  • Taxonomists have fought about what kind of bird it really is

In 1888, the Portuguese naturalist Francisco Newton collected a specimen of an unknown bird species on São Tomé. Two years later, he found another two specimens, and with its large size and massive bill it was originally described as a weaver (family Ploceidae). However, not everyone agreed, and there was an argument about whether it was really a weaver or a finch (family Fringillidae). Eventually, most authorities agreed that it was probably a finch, but its affinities were unclear and it was rewarded its own genus, Neospiza – the new finch.

São Tomé grosbeak. Photo (c) August Thomasson.

A rare sighting! This female São Tomé grosbeak (Neospiza concolor) was photographed during our field work on São Tomé, in July 2011. Photo (c): August Thomasson (augustthomasson.weebly.com).

The type specimen is held at the Natural History Museum ornithology collections in Tring, whereas the two others were destroyed in a fire in 1978 at the National Museum of Natural History in Lisbon. After Newton’s initial collections, the São Tomé grosbeak was not sighted again for over 100 years, until it was found by Dave Sergeant three other birders in 1991! Even after its rediscovery, sightings remain very scarce. Until recently, the official population size estimate has been less than 50 individuals, but recent censusing efforts by Ricardo de Lima and colleagues suggest that it might not be just that bad. Continue reading

Awarded a three-year postdoc!

I am very happy to announce that last week the Swedish Research Council awarded me a SEK 3,150,000 grant to do a three-year postdoc in the Cresko Lab at the Institute of Ecology and Evolution, University of Oregon. I will dive into the world of syngnathid fish and explore the development and the evolution of the snouts of pipefish and seahorses, learning a whole bunch of new methods along the way. I very much look forward to joining Bill and his lab in 2017! I also look forward to seeing the efforts of Bill and colleagues turn into reality, with UO’s recently presented plans for the new Knight Campus for Accelerating Scientific Impact. Check out the presentation, featuring Bill and others.

Double-stained skull of a gulf pipefish (Syngnathus scovelli), illustrating the elongated snout of syngnathids. Image from the Cresko lab.

Double-stained skull of a gulf pipefish (Syngnathus scovelli), illustrating the elongated snout of syngnathids. Image from the Cresko lab.

A jumble of larks – cryptic taxa and paraphyletic species galore

| The original paper may be accessed for free through August 11 2016, using the following link: Stervander et al. 2016 MPE |

A couple of years ago, Alström et al. (2013) revealed that larks (Alaudidae) comprised unusually many examples of both cryptic taxa (whose evolutionary and taxonomic distinctness have gone overlooked, owing to phenotypic similarity to other taxa) and convergent evolution among unrelated species. One striking example of the latter was the species pair White-winged Lark Alauda leucoptera and Mongolian Lark Melanocorypha mongolica (Figure 1, upper panel), which display very similar plumage, and have been assumed to be closely related. Instead, they turned out to be of two different genera, separated since 11 million years ago. Likewise, the two clades which have traditionally formed the genus Calandrella, have been separated for 12 million years, and are not at all each other’s closest relatives, despite superficial similarities (Figure 1 middle panel). Urban Olsson, Per Alström, and others are currently looking closely into the clade which, following their recommendation, is now known as the genus Alaudala. Together with Per and Urban, Ulf Ottosson, Bengt Hansson, and Staffan Bensch, I dived into trying to sort out the phylogenetic relationships of the remaining Calandrella clade.

Figure 1 (from Stervander 2015). Larks (family Alaudidae) display strong adaptations in bill morphology and plumage, and recent studies have revealed both convergent evolution and cryptic taxa. Alström et al. (2013) demonstrated an extreme case of convergent evolution in the White-winged Lark Alauda leucoptera (top left) and the Mongolian Lark Melanocorypha mongolica (top right), previously thought to be congeneric. We confirmed that Calandrella [brachydactyla] dukhunensis (middle left) is a separate species from the Greater Short-toed Lark C. brachydactyla (middle right), more closely related to Hume’s Short-toed Lark C. acutirostris, though it morphologically resembles the Greater Short-toed lark. We also show that C. blanfordi daaroodensis and C. b. eremica form a clade that split over four million years ago from C. b. blanfordi and C. erlangeri, which are recently split sister taxa (bottom). Photos, with permission for use in Stervander (2015): Kari Eischer (top left), David Thorns (top right), Matt Poll (middle left), Juan Lacruz (middle right), Martin Stervander with permission from the British Museum of Natural History (bottom).

Figure 1 (from Stervander 2015). Larks (family Alaudidae) display strong adaptations in bill morphology and plumage, and recent studies have revealed both convergent evolution and cryptic taxa. Alström et al. (2013) demonstrated an extreme case of convergent evolution in the White-winged Lark Alauda leucoptera (top left) and the Mongolian Lark Melanocorypha mongolica (top right), previously thought to be congeneric. We confirmed that Calandrella [brachydactyla] dukhunensis (middle left) is a separate species from the Greater Short-toed Lark C. brachydactyla (middle right), more closely related to Hume’s Short-toed Lark C. acutirostris, though it morphologically resembles the Greater Short-toed lark. We also show that C. blanfordi daaroodensis and C. b. eremica form a clade that split over four million years ago from C. b. blanfordi and C. erlangeri, which are recently split sister taxa (bottom). Photos, with permission for use in Stervander (2015): Kari Eischer (top left), David Thorns (top right), Matt Poll (middle left), Juan Lacruz (middle right), Martin Stervander with permission from the British Museum of Natural History (bottom).

My curiosity dates back to the early 2000’s, when a small and isolated population of Red-capped Larks C. cinerea was rediscovered close to the Nigerian research institute APLORI, where I have been teaching. The Jos plateau, in central Nigeria, is a curious distribution outlier for this species, which is common in Southern Africa, but has its otherwise most northerly distribution in Congo – over 1,000 km away. Continue reading

Pipefish in the pipeline

I am currently intensifying the planning and development of my intended postdoc project, with visits to two research groups in the coming few weeks. I am very happy to spend my birthday in Dominic Wright’s group at Linköping University, on May 12, and then and join the Cresko Lab with Bill Cresko, Susie Bassham, Clay Small, and Allison Fuiten at the University of Oregon in early June. We will all chat about cool future studies, making use of an organism with extreme adaptations – the pipefish – and one of the foremost biological model systems – the zebrafish.

S_scovelli

Illustration ©: Joseph R. Tomelleri

Defended and done!

Stervander_thesis_cover_LUOn 18 December 2015, I finally defended my PhD thesis, entitled On Speciation in Birds – Genomic Signatures across Space and Time. (Cover artwork, the São Tomé grosbeak Neospiza concolor, by Peter Nilsson)

I was lucky enough to have Professor Trevor Price, University of Chicago, as faculty opponent, and I thoroughly enjoyed our discussions. Having written the landmark book Speciation in Birds, there is probably no single person who would be more fit as opponent. Below is a glimpse of the two of us fighting about exactly what tree topology that represent different colonization and speciation scenarios.

I currently finish some remaining work on finch radiations, while preparing postdoc grant applications. (Or perhaps you have a great project and good funding? Let me know…)

Trevor_Martin

Again and again and again – evolutionary charter trips to the Canary Islands

In a recently accepted paper in Molecular Ecology, we conclude that blue tits have colonised the Canary Islands from Africa no less than three times, but contrary to recent suggestions they did not back colonise mainland Africa from the islands. We combined traditional DNA sequencing on a large scale with massively parallel sequencing (“next generation sequencing”) and combine their respective strengths.

A demographic reconstruction reveals that the populations on the eastern Canary Islands Fuerteventura and Lanzarote have undergone recent population bottlenecks, while the long-term population sizes in northwest Africa have been stable, clearly supporting that the mainland populations have acted as a source for the colonisation of Fuerteventura and Lanzarote, and not the other way around.

Coalescense species trees of the Cyanistes tit complex. Values along branches represent posterior probabilities (PP), and * signifies PP = 1.0. For further information, see our paper.

Coalescense species trees of the Cyanistes tit complex. Values along branches represent posterior probabilities (PP), and * signifies PP = 1.0. For further information, see our paper. Illustrations (c) Martí Franch.

The phylogenetic relationships between the blue tit populations of the Canary Islands are truly intricate. Continue reading

Hello!

Looking happier than the bluebottle.

Welcome to my site! I am a keen ornithologist and evolutionary biologist, who just finished my PhD project at Lund University, Sweden, on speciation in birds. Does it seem like a rather broad theme? It is, and to cover it I am working with several study systems, of which many are made up by small radiations on isolated islands. I love doing field work, but for these projects I have spent the main part of my time in the lab, where I am applying both traditional genetic tecniques and state of the art “next generation” DNA sequencing. When asked to describe my project to non-biologists I say “think Darwin 2.0”, which should give a good hint! Read more about this in the Research section.