Conservation through connectivity: can isotopic gradients in Africa reveal winter quarters of a migratory bird?

Reichlin, Thomas S.; Hobson, Keith A.; Wilgenburg, Steven L. Van; Schaub, Michael; Wassenaar, Leonard I.; Martín‐Vivaldi, Manuel; Arlettaz, Raphaël; Jenni, Lukas

doi:10.1007/s00442-012-2418-5

Cited by 24 publications

(29 citation statements)

References 43 publications

(68 reference statements)

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“…However, the known wild African grey parrot feathers reflected differing d 2 H values relative to their capture sites and aligned with the suggested weak east to west gradient in d 2 H precipitation values across central Africa (Hobson, 2005;Bairlein, Norris & Nagel, 2012;Reichlin, Hobson & Wilgenburg, 2013;Guti errez-Exp osito, Ram ırez & Af an, 2015). However, the known wild African grey parrot feathers reflected differing d 2 H values relative to their capture sites and aligned with the suggested weak east to west gradient in d 2 H precipitation values across central Africa (Hobson, 2005;Bairlein, Norris & Nagel, 2012;Reichlin, Hobson & Wilgenburg, 2013;Guti errez-Exp osito, Ram ırez & Af an, 2015).…”

Section: Discussionmentioning

confidence: 51%

Stable isotope analyses as a forensic tool to monitor illegally traded African grey parrots

Alexander

Downs

Butler

et al. 2018

Animal Conservation

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Stable isotope analyses are a powerful tool in understanding diets, defining trophic networks, inferring geographical origins of animals and in forensic tracing of the origins of deceased humans or illegally traded animal and plant material. African grey parrots Psittacus erithacus are one of the most traded animal species in the world, and the origin of confiscated illegal or deceased specimens are often unknown. We measured stable isotope values (d 13 C, d 15 N and d 2 H) in different African grey parrots (n = 32) and determined feather type (i.e. primary, tail, breast) standardization values for comparing individuals. d 13 C and d 2 H values differed between known wild (n = 42) and captive (n = 50) birds when standardized for feather type, but not for d 15 N. d 13 C and d 2 H values in feathers from a consignment of African grey parrots (n = 100), all of which were deceased, aligned significantly with that of known wild birds. We suggest that further analyses of feathers, across a range of spatial and temporal scales, will enhance stable isotope analyses as a valuable tool in monitoring and combatting the trade of African grey parrots. Furthermore, the use of stable isotope analyses may improve the monitoring of illegally traded bird species, and other wildlife, across the globe.

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Section: Discussionmentioning

confidence: 51%

Stable isotope analyses as a forensic tool to monitor illegally traded African grey parrots

Alexander

Downs

Butler

et al. 2018

Animal Conservation

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“…Several studies have been validating this assumption in recent years [24], [46], [47] yielding variable results depending on species and isotopes used. Ideally, flycatcher winter-grown feather isotope values should be determined across their wintering ranges to validate our assignments and function as a reference map or calibration for assigning individuals caught on the breeding grounds to a more specific wintering location.…”

Section: Discussionmentioning

confidence: 99%

“…Secondly, individual tracking devices such as light-level geolocators that can even be carried by small birds the size of flycatchers, can be combined with isotope analyses to try to cross-validate the results of the isotope assignments (or vice versa ) or improve the assignment to wintering grounds [47]–[49], but see [50] for a critical meta-analysis showing a negative effect of geolocators on fitness for small aerial insectivores). Geolocators furthermore provide valuable information on the migration route of the individual [8], which would be very informative for studies like ours, assuming migration route was not impacted by the presence of a geolocator.…”

Section: Discussionmentioning

confidence: 99%

Identifying the African Wintering Grounds of Hybrid Flycatchers Using a Multi–Isotope (δ2H, δ13C, δ15N) Assignment Approach

et al. 2014

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Migratory routes and wintering grounds can have important fitness consequences, which can lead to divergent selection on populations or taxa differing in their migratory itinerary. Collared (Ficedula albicollis) and pied (F. hypoleuca) flycatchers breeding in Europe and wintering in different sub-Saharan regions have distinct migratory routes on the eastern and western sides of the Sahara desert, respectively. In an earlier paper, we showed that hybrids of the two species did not incur reduced winter survival, which would be expected if their migration strategy had been a mix of the parent species' strategies potentially resulting in an intermediate route crossing the Sahara desert to different wintering grounds. Previously, we compared isotope ratios and found no significant difference in stable-nitrogen isotope ratios (δ 15N) in winter-grown feathers between the parental species and hybrids, but stable-carbon isotope ratios (δ 13C) in hybrids significantly clustered only with those of pied flycatchers. We followed up on these findings and additionally analyzed the same feathers for stable-hydrogen isotope ratios (δ 2H) and conducted spatially explicit multi-isotope assignment analyses. The assignment results overlapped with presumed wintering ranges of the two species, highlighting the efficacy of the method. In contrast to earlier findings, hybrids clustered with both parental species, though most strongly with pied flycatcher.

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“…Unfortunately, the latter usually exist mainly for northern hemisphere regions [19]. Thus, predictions with sufficiently high confidence are possible for certain regions on Earth, whereas for other areas like the African continent such predictions might be hard to establish [20]. …”

Section: Introductionmentioning

confidence: 99%

Matching geographical assignment by stable isotopes with African non-breeding sites of barn swallows Hirundo rustica tracked by geolocation

Seifert¹,

Ambrosini

Bontempo

et al. 2018

PLoS ONE

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Knowledge on whereabouts within the annual cycle of migratory species is prerequisite for many aspects in ecology and biological conservation. Spatial assignments of stable isotopes archived in tissues allows for later inference on sites where the specific tissue had been grown. It has been rarely tested whether spatial assignments match directly tracked non-breeding residences, especially for migratory songbirds. We here compare assignments of stable isotopes from feathers of Palaearctic Barn swallows Hirundo rustica with their African non-breeding residence sites tracked by geolocation.Assignments based on δ2H, δ13C and δ15N isotope compositions delineate three main non-breeding regions: a main cluster in central Africa, a second in West Africa, and the third cluster in Northern Africa. Using δ13C, δ15N only, non-breeding sites ranged from clusters in West/Southwest Africa to South East Africa with a centre in Central Africa. The non-breeding areas (50% and 75% Kernel density estimates, KDE) of the birds tracked by geolocation stretched from West Africa via central Africa to southern Africa. We found little overlap of 0.3% (assuming a 1:1 odds ratio) to 1.4% (3:1 odds ratio) in the three element assignments and KDEs for only 2 and 13 individuals out of 32 birds. Assignment maps for two elements (δ13C, δ15N) and KDEs showed higher consistencies with an overlap of 3.6 and 8.5% for 12 and 18 birds. We argue that the low matching between stable isotope assignments and non-breeding sites in our study arise from insufficient baseline data for Africa (concerning both isoscapes and specific discrimination functions). However, other factors like aerial foraging habit of the species, and a potential mismatch of non-breeding site location and the spatial origin of aerial plankton might further hamper accurate assignments. Finally we call for concerted analyses of tissues i.e. feathers and claws of birds which are grown at known sites across the continent and from species with various ecological requirements (diverse habitats, foraging behaviours, and diet compositions) to establish isoscapes for general applicability.

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Conservation through connectivity: can isotopic gradients in Africa reveal winter quarters of a migratory bird?

Cited by 24 publications

References 43 publications

Stable isotope analyses as a forensic tool to monitor illegally traded African grey parrots

Stable isotope analyses as a forensic tool to monitor illegally traded African grey parrots

Identifying the African Wintering Grounds of Hybrid Flycatchers Using a Multi–Isotope (δ2H, δ13C, δ15N) Assignment Approach

Matching geographical assignment by stable isotopes with African non-breeding sites of barn swallows Hirundo rustica tracked by geolocation

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