Northern Wheatear Oenanthe Research Articles

Can Mitogenomes of the Northern Wheatear (Oenanthe oenanthe) Reconstruct Its Phylogeography and Reveal the Origin of Migrant Birds?

The Northern Wheatear (Oenanthe oenanthe, including the nominate and the two subspecies O. o. leucorhoa and O. o. libanotica) and the Seebohm’s Wheatear (Oenanthe seebohmi) are today regarded as two distinct species. Before, all four taxa were regarded as four subspecies of the Northern Wheatear. Their classification has exclusively been based on ecological and morphological traits, while their molecular characterization is still missing. With this study, we used next-generation sequencing to assemble 117 complete mitochondrial genomes covering O. o. oenanthe, O. o. leucorhoa and O. seebohmi. We compared the resolution power of each individual mitochondrial marker and concatenated marker sets to reconstruct the phylogeny and estimate speciation times of three taxa. Moreover, we tried to identify the origin of migratory wheatears caught on Helgoland (Germany) and on Crete (Greece). Mitogenome analysis revealed two different ancient lineages that separated around 400,000 years ago. Both lineages consisted of a mix of subspecies and species. The phylogenetic trees, as well as haplotype networks are incongruent with the present morphology-based classification. Mitogenome could not distinguish these presumed species. The genetic panmixia among present populations and taxa might be the consequence of mitochondrial introgression between ancient wheatear populations.

Earlier spring passage of ‘Greenlandic’ Northern Wheatears Oenanthe o. leucorhoa on the coast of Belgium

ABSTRACT In temperate regions many migratory bird species have advanced their spring arrival to the breeding grounds in recent decades but such changes are much less known among Arctic species. Here we report on long-term changes in the spring passage of ‘Greenlandic’ Northern Wheatears (Oenanthe o. leucorhoa), as revealed by trapping and ringing along the coast of southwestern Belgium. Between 1990 and 2018, these wheatears advanced their average timing of spring passage by 2.9 days for females and by 2.5 days for males. Neither regional weather variables in spring nor the North Atlantic Oscillation Index was found to be correlated with these changes.

Wheatear molt and assignment tests: ongoing lessons in using stable isotopes to infer origins

In an earlier paper (Rocque et al. 2006), we attempted to assign two generations of feathers in three species of intercontinental migrants to their respective breeding and wintering areas using stable isotopes. We found that while two species of Pluvialis plovers that breed in Alaska and winter on different sides of the Pacific Ocean (South America versus Asia and the South Pacific) showed significant differences between summerand winter-grown feathers, we could not statistically separate feathers grown on the two continentally different wintering areas. Nor could we assign summer-grown feathers to within thousands of kilometers of their actual origin using the common approach of a North American isotope (dD) isocline map. In Alaska-breeding Northern Wheatears (Oenanthe oenanthe), which winter in Africa, we found no significant differences between summerand (presumed) wintergrown feathers. Larson and Hobson (2009) helpfully point out a molt-related problem with our study, specifically with respect to where our presumed winter-grown Northern Wheatear feathers were actually grown. We welcome the opportunity to draw attention to wheatear molt, in which we made an error: the body plumage color changes in O. oenanthe between autumn and spring must be one of the most dramatic to occur in highlatitude birds due to feather wear and not to molt (Fig. 1). Measurements of 10 back feathers from five males in fresh basic plumage showed that approximately one-third (average 36.5%) of the feather length is worn off to achieve this color change. Thus, most if not all of our presumed winter-grown back feathers from adult Northern Wheatears were grown in Alaska, not Africa. This is mea culpa for DAR and KW. We overestimated the extent of the prealternate molt and appreciate the input from other colleagues and now Larson and Hobson (2009) that provides us the opportunity to correct this error. This recognition helps us understand why this group of feathers did not differ significantly from secondaries known to have grown during the previous breeding season in Alaska on these same birds. We hope this prevents others from committing a similar error, for such mistakes only add to the pitfalls associated with using stable isotope analysis to infer origins and movement patterns of animals. However, the presumed winter-grown wheatear back feathers represented only one of six datasets in our study, and we consider that the other conclusions remain robust. In addressing our Pluvialis data, Larson and Hobson (2009) do not dispute the spatial location of feather growth (in the tropics on different sides of the Pacific Ocean in the respective species). Instead, they provide a series of reasons why winter-grown feathers might have high variance in dD (as we did also). They suggest that we should have excluded samples for which dC was less negative than -20% because these samples represent feeding in the Communicated by F. Bairlein.

DO NEARCTIC NORTHERN WHEATEARS (OENANTHE OENANTHE LEUCORHOA) MIGRATE NONSTOP TO AFRICA?

Abstract We present data suggesting that Northern Wheatears (Oenanthe oenanthe leucorhoa) breeding in West Greenland and Canada may be able to accomplish migration to their wintering grounds in West Africa in one direct, transatlantic crossing of more than 4000 km (great circle distance). This conclusion is based on analyses of wing lengths, body weights, and timing of departure from West Greenland and arrival on an island 350 km off the coast of Morocco. Previously, it has been suggested that Nearctic wheatears migrate to Africa by a two-step journey, the first leg comprising a shorter transatlantic crossing to western Europe. A long, direct flight has previously been considered unfeasible as the predicted flight costs were considered to be too high. However, recent insights in aerodynamic theory make these long ocean crossings appear more feasible, especially when taking the use of tailwinds into account.

Prey of Peregrine Falcons Breeding in West Greenland

Previous studies on the diet of Peregrine Falcons (Falco peregrinus) in Greenland were based primarily on prey remains, an indirect technique that may produce biased results. Earlier estimates of prey biomass are too general and speculative to be conclusive. No other study provided data on the age of prey species or showed that Rock Ptarmigan (Lagopus mutus) can be an important component in the diet of Greenland peregrines. We used direct observations of prey deliveries and collection of prey remains to assess prey (in terms of frequency of occurrence and biomass) of breeding Peregrine Falcons in West Greenland. We also determined prey selection in relation to local prey availability. During 492 hr of observation at two eyries we found that four small passerines-Lapland Longspur (Calcarius lapponicus), Northern Wheatear (Oenanthe oenanthe), Common Redpoll (Carduelis flammea), and Snow Bunting (Plectrophenax nivalis)-contributed over 80% of the prey items delivered, with the longspur being the principal prey species in terms of frequency of occurrence and biomass. However, ptarmigan contributed almost as much biomass as longspurs at one eyrie. Fledglings of all these bird species provided the majority of items and biomass at both eyries. Analysis of 676 prey items from prey remains at 159 eyries showed similar frequencies and rankings for the prey species comprising the majority of the diet of Peregrine Falcons as determined by prey deliveries. Lapland Longspur was taken in proportion to its availability near two eyries; ptarmigan and Snow Buntings were taken more frequently than expected. Local differences in prey use (especially ptarmigan) were found.