Portal to the Lesser White-fronted Goose

Translocation/Reintroduction/Reinforcement

Plans and programmes for translocation/reintroduction of LWfG have been debated intensively for many years. The Fennoscandian LWfG conservation project has taken (past and present) a critical stand towards these programmes for the LWfG for a number of reasons. The most frequently discussed questions are related to genetic disturbance (i.e. genetic composition of the stocks used for reintroduction) and manipulation of flyways. There are many reasons to be critical to both the suitability of the current manipulated population (in Sweden) and the sustainability of ongoing (Sweden) and planned (Germany) programs.

International conservation activities for Lesser White-fronted Geese within the Western Palearctic follow the priorities outlined in the AEWA International Single Species Action Plan (ISSAP) adopted in 2008, the focus of which is clearly on the conservation of the original wild populations. Both this International Action Plan, as well as its predecessor adopted under the framework of the Council of Europe in 1996, express concerns regarding the potential threat posed to the existing Fennoscandian population by the free-flying Lesser White-fronted Geese released in Sweden.

The ongoing disagreements regarding the captive breeding, supplementation and reintroduction of Lesser Whi<br>te-fronted Geese in Europe have over the years severely hampered the implementation of conservation action for the remaining wild populations of Lesser White-fronted Geese by repeatedly drawing away the focus of the international discussion from the urgent conservation priorities for the species. Repeated attempts to revise the International Single Species Action Plan for the Lesser White-fronted Goose have, for example, effectively been halted due to these ongoing controversies. In addition, and more worryingly, the release projects themselves are increasingly considered to be directly detrimental to the conservation and future of the Fennoscandian population.

Genetic factors/aspects:

Based on studies of captive LWfG populations, hybridisation between LWfG and White-fronted Goose Anser albifrons has occurred during the captive history: the captive LWfG carry the mitochondrial DNA of Anser albifrons (cf. Ruokonen 2001), and evidently, also part of the nuclear DNA of the captive LWfG is inherited from Anser albifrons. Also hybridization with Greylag Goose Anser anser has been proved for the captive stocks used for introductions in Europe.

Because the mitochondrial and nuclear DNA of Anser albifrons are not linked in the captive LWfG stocks, eliminating only the individuals with the mitochondrial DNA of Anser albifrons does not solve the problem, because there are also individuals possessing mitochondrial DNA of LWfG, but nuclear DNA of both of the species.

Hybridisation between these species in the wild has not been recorded in the DNA studies, even though more than 100 individuals of LWfG and White-fronted Geese have been sampled covering the whole distribution range of LWfG, and despite the fact that the two species occur in mixed flocks during migration and wintering when pair formation is supposed to take place (Ruokonen 2001).

Based on the mitochondrial DNA, the wild Fennoscandian LWfG population differs significantly from other LWfG sub-populations and thus the Fennoscandian population is considered as a separate management unit in conservation biology (Ruokonen 2001).

The present free flying population in Sweden consists of a mixture of western and eastern LWfG mitochondrial DNA types, with introgression of genes from White-fronted Goose Anser albifrons and Greylag Goose Anser anser and recent genetic analyses (Díez-del-Molino et al. 2020) shows the population being very different from the original wild Fennoscandian and Russian western main populations. The latter study also has a lot of weaknesses, but especially the use of one White-fronetd Goose individual with unknown origin (and ssp.) makes it useless to infer anything about the history of hybridization in captivity for the stocks used.

The use of Barnacle Goose Branta leucopsis as foster parents when manipulating the migration route has led to a significant level of hybridization between these two species, with also second generation hybrids recorded.

Sweden has since 2010 again started releasing birds in the breeding area. These are of supposedly of Russian origin, and released as goslings and 1 year old birds without assistance of Barnacle Goose as foster parents. That this will alter the negative impact of the existing hybrid population is doubtfull all the time the existing hybrids likely have an advantage in lower winter mortality due to the alteration of habitat preferences seen in this population (see below).

Captive and wild populations are subjected to different selection pressures. Virtually all captive-bred populations are going through a strong selection process adapting them to captivity, which together with genetic drift can result in genetic divergence of wild and captive populations (Waters et al. 2015). Captive breeding and the reintroduction process, involving direct and indirect human impact, can cause high non-random differences in breeding success and mortality among the captive population (McDougall et al. 2005, Gomes Destro et al. 2018). Reintroduced individuals may also show loss of local adaptation and can introduce non-native genes to the wild populations (Champagnon et al. 2012). Several studies have shown that captive-bred individuals lose characteristics that are vital for survival in nature, and the Swedish free flying population is suffering from extremely low survival which have been calculated to less than 61 % for adults after 2010 (Schekkerman & Koffijberg 2019).

Manipulation of migration routes:

Specifically, in addition to original hybrid origin, the Swedish reintroduced/restocked population was manipulated to change its wintering area by the use of Barnacle geese Branta leucopsis as foster parents. As a consequence this population now winters in areas that are not traditional wintering areas, contrary to unsubstantiated claims by reintroduction/restocking stake holders. Another negative side effect of this manipulation is the use of other undesired sites, such as city parks for staging and moulting. Current releases in Sweden of captive birds originating from wild caught Russian breeders do not alter the fact that the Swedish re-stocking project struggle with regular appearance of hybrids, also of LWfG x Barnacle Goose origin.

Behavioral (and other) aspects:

To assume that the release of new “pure” birds would swamp the existing hybrids in this population is naïve. This hybrid population has, contrary to wild LWfG seen in Fennoscandia and Russia, made the transition to feed on cultural habitats/ farmland especially duting winter in the Netherlands & Germany, a trait not shared by wild LWfG and Brent Goose Branta bernicla. Wild, natural populations of LWfG are habitat specialists, exclusively exploiting natural steppe habitat during winter.

Present position of the Fennoscandian LWfG conservation project to reintroduction activity:

Reintroduction projects are not given priority in the International Action Plan for the LWfG published by the Council of Europe in 2008, but are mentioned as a last resort if all other actions fail and only by following the IUCN criteria for translocation/re-introduction. Even the most critically endangered of all LWfG sub-populations, the Fennoscandian breeding population, has still a chance for recovery. One international document providing guidance for the introduction, along with the International Action Plan for LWfG, is the IUCN Species Survival Commission (SSC) guidelines for reintroduction programmes. According to the IUCN guidelines (IUCN/SSC 2013), the captive stock used to restock the wild population should be genetically as close as possible to the wild population that was extirpated from the reintroduction area. This is not the case with the current captive stocks used (or planned to be used) in the LWfG reintroduction programmes in question. Also, according to the IUCN criteria, there should be no remnant wild population in the release area, to prevent spread of disease, social disruption and introduction of alien genes in the wild population. If the reintroduction programmes would be successful by establishing one or more new populations in Fennoscandia (as they naturally aim to), the reintroduced population would relatively soon get in contact with the wild population either on the breeding grounds or along the migration routes.

First generation hybrid A.erythropus x B. leucopsis, Turku, Finland, 27 May 2008 © Kalle Rainio/Tarsiger.com. Also second generation hybrids have been found in Sweden. Pictures and discussions of these can be found at the Swedish report system for birds.

In addition to the dubious genetic composition of the captive LWfG stocks, the Fennoscandian LWfG conservation project has stressed repeatedly, that in the present situation the conservation efforts to save the wild populations are very urgent. On the other hand, there is no urgency to pay much effort to – or implement new – reintroduction projects in the present situation, where the genetic suitability of the captive LWfG stocks for reintroduction is at best questionable. Resources spent on the reintroduction projects in the current situation can also be viewed as a waste of the time, effort and resources, that should be directed towards eliminating the threats such as excess hunting, poaching, habitat destruction in the struggle for rescuing the wild LWfG populations and their habitats.

At present the wild Fennoscandian population increase with >20% per year and as long the ongoing conservation efforts are successful, the Fennoscandian LWfG conservation project strongly warns against any reintroduction projects that may harm or jeopardize the small and vulnerable wild population of LWfG in Europe.

Lots of Pictures of hybrid birds in Sweden are to found in the Swedish observation system. Since 1991 these hybrid accounts for 14% of all records on Lesser White-fronted Goose in Sweden.

Publications related to restocking/reintroduction

Sweden has published an National Action Plan for the Lesser White-fronted Goose, but this does not distinguish between wild and reintroduced birds. The NAP mainly concerns the restocked/reintroduced population with a manipulated migration route.

Swedish National Action Plan for the reintroduced Lesser White-fronted Goose available in Swedish with English summary, published in 2011.

Latest sightings of LWfGs with reintroduced or escapee origin

Location: Nemunas Delta, Sausgalviai, Sausgalviai, Klaipėda, Lithuania

Observed: 6 LWFG (Swedish) - 2 Ad 4 2cy.

Details: All the birds were ringed, two had GPS transmitters on their necks. Vytautas Eigirdas

Vytautas Eigirdas

Location: Nemunas Delta, Suvernai, Suvernai, Silute, Lithuania

Observed: 3 LWFG (Swedish) - 3 Ad.

Details: 3 ringed adult birds. Vytautas Eigirdas

Vytautas Eigirdas

Location: Nemunas delta, Silute, Silute, Silute, Lithuania

Observed: 7 LWFG (Swedish) - 5 Ad 1 2cy.

Details: At least 4 adult birds were ringed, 3 rings were identified (N7 N), (NH N), (WP G). The rings of one bird could not be identified. One bird really didn’t have rings, two more couldn’t be seen well. 5 birds were adults, one 2 cy, ne age could not be determined. Vytautas Eigirdas

Vytautas Eigirdas

Location: Nemunas Delta, Suvernai, Suvernai, Silute, Lithuania

Observed: 1 LWFG (Swedish) - 1 Ad.

Details: Bird was ringed (GP O) Vytautas Eigirdas

Nemunas Delta Vytautas Eigirdas

Location: Alnesfjæra, Alnesfjæra, Nord-Trøndelag, Norway

Observed: 1 LWFG (Swedish) - 1 2cy.

Details: Reported via the bird alarm service BAND and also on the Norwegian Species Reporting System (Artsobservasjoner.no). Feeding at Håa, Nesset near Levanger (geese here tend to roost at Alnefjæra, hence the chosen location for this sighting). Bird is in second-calendar year. Colour-ringed: Left - black over metal ring, right: blue ring with letter D (in white). This is a bird released in Sweden in 2017. various including - https://artsobservasjoner.no/Sighting/19248087

Location: Nemunas Delta, , Klaipėda, Lithuania

Observed: 1 LWFG (Swedish).

Details: Observed during Goose Specialits Group excursion to Nemunas Delta. Fist reported earlier in day by National Park staff. The bird had a black colour-ring with the letter C (in white) on one leg, and a colour ring above the metal ring on other leg. I cant remember which was reported on which leg, but the bird is without a doubt from the Swedish reintroduction project. Nemunas Delta National Park ranger via Paul Shimmings

Location: Harku vaald, Humala, Humala, Harjumaa, Estonia

Observed: 1 LWFG (Swedish).

Details: Seen on the field with White-fronts and Bean Geese. Green colour ring on the leg. Ranno Puumets

Location: Znin, Rogowo, Rogowo, kujawsko-[pomorskie, Poland

Observed: 1 LWFG - 1 Ad.

Details: Bird with black neckband A25 Bartosz Krakowski

Bartosz Krakowski

Location: Kallvatnet, Kallvatnet, Rana, Norway

Observed: 4 LWFG - 4 juv.

Details: All birds stemming from the Swedish reintroduction project had a blue mark on right leg, and on left leg the following: 1) yellow “A”, 2) dark green (or black) “5”, 3) dark green (or black) “7”, 4) yellow “N”. The birds were seeking out the observer. Observed by Benny Sætermo, conveyed by Tomas Aarvak

The birds came to the observer, and photo was taken with mobile camera. Benny Sætermo

Location: Rana, Skuggheia, Rana River, Skuggheia, Rana River, Nordland, Norway

Observed: 18 LWFG - 18 juv.

Details: observed in Rana river by a salmon fisher, at least one bird with satellite transmitter. Photo documentation exist. Benny Sætermo, conveyed by Tomas Aarvak

Location: Alvik, Luleå, Klubben, Klubben, Norrbotten, Sweden

Observed: 4 LWFG - 4 Ad.

Details: Two adult pairs found in a field with 1850 bean geese, 300 greylags, 2 white-fronts, 4 pink-feets, 1 barnacle and 15 Canada geese. Possible Swedish reintro-origin, pending analyses of belly patches. Tomas Aarvak / BirdLife Norway

One of four adults. Tomas Aarvak

Location: Nemunas Delta, Rupkalviai, Rupkalviai, Klaipėda, Lithuania

Observed: 1 LWFG - 1 Ad.

Details: Rings: L: Yellow (N) R: Red and metal . Boris Belchev _ LWfG research team Lithuania

A bird was feeding together with GWf and Barnacle Geese at Rupkalviai pastures. Boris Belchev

Location: Åkersvika, Åkersvika, Hedmark, Norway

Observed: 2 LWFG.

Details: Colour ringed, one with on left and red + metal on right. The other with white on left and yellow + metal on right. Birds from the Swedish reintroduction project. http://artsobservasjoner.no/fugler