First experience from translocation of Aquatic Warbler - ’s rarest passerie ad log distat igrat

By Žyatas Morkvėas, Baltic environmental forum, Aquatic Warbler ( paludicola Vieillot) The most threatened species of continental Europe

• World population - 11 000 singing males • Decline by 95% in last 100 years; • Since 2014 breeds in 4 countries in the world

• IUCN category vulnerable A2c. • Protected under Annex I of the EU Directive, • Bern and Bonn conventions. Project activities besides translocation • Developing stepping stone habitat network concept; • Habitat restoration; • Establishing biomass processing business to sustain long-term habitat maintenance; • Stakeholder communication, awareness raising. The Project aims to prove if translocation could be a mechanism to re-establish Aquatic Warbler in parts of former range as habitat conditions allow

- Does the translocation for this long distant migrant works? - If yes, then optimize the method so, it could be used as a tool when necessary

May 25th - July 7th 2018: 50 birds from (Zvaniec fen mire) to Lithuania (Zuvintas fen mires) Translocation principle • Movement young broods • Imprinting for Acrocephalus in 30-50 days of age at release site; • Monitoring return of the birds next season.

Source site - Zvaniec fen mire Release site - Žuvitas fen mire • 14 000 ha area; • Compact site (>200 ha) – easy to • The largest AW population globally (2- monitor return of translocated birds; 4 thous. singing males 20-30 % of • Local population gradually decreased global population); • Good location in the context of stepping-stone habitat network Stage 1: Search of nests and pick up • Prescribed burning applied to the habitat made searching of nests a lot easier • Brood pickup at 7-10 days of chick age; • Feeding interval – 20 min. Stage 2: Transfer of the nestlings • Transport distance ~500 km during night when birds are asleep. • Crossing of Belarus-Lithuania boarder required long preparations.

Translocation menu: INSECTS • Wild insects: • horseflies • grasshoppers etc. • At eggs. • Cultivated insects: • mealworms, • crickets, • cockroach • Bee larvae

Mixture: 1) at eggs, 2) Hard-boilded egg, 3) Special vitamin D mixture, 4) Fresh leaves (Stellaria media, Taraxacum officinale), 5) Crushed Gammarus. Stage 3: Growing the young in cages • Separate cage for each brood; • Constant background audio record: sound of the fen mire; • Regular sound records of singing adults; Stage 3: Growing the young in cages • Feeding interval – from 20 min. to 1 hour; • Kept in cages until they were able to feed themselves from feeding plate;

Stage 3: Growing the young in cages • Observed aggressive behaviour outbursts (probably due to lack of space and teenager factor) – sign for readiness for outdoor aviaries Stage 4: Moving to a field aviary

Stage 5: Soft-release of the birds Translocation diet – facing challenges • Absence of insects at the release site (weather conditions, season 2 weeks behind; • Balancing the right vitamins Involvement of volunteers • App. 50 people involved; • Involvement of farmers to establish relationship with birds

Observations bringing hope for success: • Birds learned to hunt for food; • Looks well fit; • After release – regular return to the aviaries site; • Observed feeding outside aviaries; • Keep distance from human Success criteria and achievements so far

Until the time of release chicks survival rate has to be no less than 75% Achieved survival rate 98 %

At least one translocated bird has to come back after wintering to release site To be monitored in 2019 Predator management • Electric fencing • Trap cameras • Aviaries diged in the ground 20 cm depth • Constant personal presence (living in the area) Addressing migration • Special geolocators attached to 60 wild individuals to clarify currently unknown wintering location of north-east population • Birds with geolocators will be recaptured in summer 2019

Geolocator device (weight 0,38 g.)

Aquatic Warbler with geolocator. Communicating translocation Future plans • Monitoring of success (returned birds after migration); • 2019 - 2nd year of translocation for another 50 birds; • Handbook on translocation method application. Contact: Žyatas Morkvėas, Baltic environmental forum, Lithuania [email protected] www.bef.lt

Aquatic warbler conservation project in Lithuania and Belarus https://meldine.lt/en/