Matthew Mitchell

#ExtinctInTheWild (EW) species are some of the most at risk in the world, existing only in human care. I’m a PhD student at @zslofficial.bsky.social and @ucl-c4ia.bsky.social studying how time spent in human care may affect EW bird recovery #BOU2025 #Ornithology #ConservationScience 🌍 🦤 🧪 1/6

zslpublications.onlinelibrary.wiley.comParental Age, Inbreeding and Incubation Method Influence Extremely Low Hatching Success in the Ex‐Situ Population of the Extinct in the Wild SihekReproductive success rates are a key parameter determining the recovery potential of ex-situ managed threatened species, with high rates often being required to produce offspring for wild releases wh...

5 Aug 2025

So happy to share that after years of hard work our paper on low hatching success in the #ExtinctInTheWild #Sihek has now been published in Animal Conservation! Read more here: zslpublications.onlinelibrary.wiley.com/doi/10.1111/... #Ornithology #ConservationScience 🌍 🦤 🧪

zsl.orgBird species lost from wild lays first eggs on new island home | The Zoological Society of LondonEndangered bird recently returned to the wild have laid first eggs on their new Pacific island home, making them the first wild eggs for the species in almost 40 years.

22 Apr 2025

So exciting to see #sihek eggs confirmed in the wild for the first time in nearly 40 years! www.zsl.org/news-and-eve... #ConservationScience 🌍 🦤 🧪 #Ornithology

Matthew Mitchell reposted

Andrew Christopher Knapp

@knapprew.bsky.social

12 Apr 2025

A very successful Adder Day 2025! The weather was almost too nice this year, the scaly fellas didn't hang around for long.

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Our results find that to best support the growth of the human-managed population of sihek so that releases can continue into the wild, younger and less-inbred males should be prioritised for breeding, and eggs should be parent incubated where possible. See shorturl.at/w0OpY to learn more! 6/6

Manuscript currently in review, with more info coming with publication - watch this space! Acknowledgements to my supervisors: @rnf.bsky.social, John Ewen, Gary Ward & Amanda Trask, co-authors Gina Ferrie, Erica Royer, Suzanne Medina & Scott Newland, and all zoos that kindly provided data.

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We began by collecting egg outcome data from many of the institutions that care for sihek, then quantified egg viability and hatching success rates before running Bayesian generalised mixed effects models to determine which factors may limit sihek reproductive success 4/6

Analysis showed that #sihek overall hatching success is only ~30%, compared to ~83% across birds and ~79% across similarly threatened birds and those under human care (doi.org/10.1111/acv....), with sire inbreeding, sire age and artificial incubation likely the driving factors behind this 5/6

Unfortunately, highly threatened birds and those under human care often suffer from low hatching success due to population bottlenecks, small population sizes and inbreeding depression amongst other reasons (doi.org/10.1111/brv...., doi.org/10.1111/acv....) 2/6