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Devi Satarkar @devisatarkar.bsky.social · 27/09/2026

Thank you so much! it’s a really cool method!

Reposted by Devi Satarkar

Ben Sheldon @sheldonbirds.bsky.social · 24/09/2026

Latest work from @devisatarkar.bsky.social DPhil thesis exploring the ecological effects that modulate the link between offspring and adult body mass in great tits. The correlation is really quite plastic! Fun collaboration with @lbliard.bsky.social @iremsepil.bsky.social @davididiaquez.bsky.social

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Devi Satarkar @devisatarkar.bsky.social · 25/09/2026

Thank you so much! I had fun learning this method – really opens up a lot of fundamental questions like this one

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Dan Baldassarre @evornithology.bsky.social · 24/09/2026

jeez this is nice work on the foundational concept P = G + E

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Devi Satarkar @devisatarkar.bsky.social · 23/09/2026

Thanks to the massive efforts of numerous fieldworkers involved in Wytham tit data collection for almost 80 years at @egioxford.bsky.social, which enables the application of cool new methods like these to fundamental questions in ecology!

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Devi Satarkar @devisatarkar.bsky.social · 23/09/2026

Check out the preprint on bioRxiv for a lot more insights on what mechanisms may be underlying the predictive link between natal and adult body mass! with @davididiaquez.bsky.social, @lbliard.bsky.social, @iremsepil.bsky.social and @sheldonbirds.bsky.social

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Devi Satarkar @devisatarkar.bsky.social · 23/09/2026

Decomposing these patterns into genetic and non-genetic components showed that they are largely driven by non-genetic individual differences! The genetic correlation between natal and adult body mass appears stable across the three environmental gradients – we didn't detect any GxE interactions 🧬 🌳

Reaction norms for the additive genetic correlation (rA in purple) and non-genetic among-individual correlation (rE in green) between nestling mass and adult body mass of great tits from Wytham Woods, UK as functions of (A) adult temperature (ºC) (average daily temperature during breeding), (B) natal temperature (ºC) (average daily temperature during development (0–15 days post hatching)), (C) adult population density (number of pairs of great tits and blue tits in the breeding year), (D) natal population density (number of pairs of great and blue tits in the hatch year), Lines show the posterior median effect sizes; shaded bands show 25–75%, 10–90%, and 5–95% credible intervals. (E) Posterior distributions of the corresponding CRN slopes (point = posterior median; thick bar = 50% CI; thin bar = 90% CI; dashed line = zero).

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Devi Satarkar @devisatarkar.bsky.social · 23/09/2026

Temperature and rainfall effects may be compensatory: In favourable (warm, dry) conditions, birds that started poorly may catch up with those that had a good start, weakening the early-to-adult link. When resources are scarce (cold, wet conditions), lighter birds can't compensate – link stays strong

(Left) Predicted correlation reaction norm shape for compensatory mechanisms: that the correlation weakens as adult conditions become more benign, (Right) Plots showing how the correlation between natal and adult body mass varies with temperature (top) and rainfall (bottom) during breeding

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Devi Satarkar @devisatarkar.bsky.social · 23/09/2026

Why would higher breeding density weaken the correlation?🤔 Perhaps resources are constrained for everyone when density is high, so even nestlings who started out heavier can't translate that advantage into higher adult mass. At low density, heavier fledglings can capitalise on abundant resources.

Plot showing how correlation between natal and adult body mass weakens as population density during breeding increases

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Devi Satarkar @devisatarkar.bsky.social · 23/09/2026

We use the covariance reaction norm method (by @jsmartin.bsky.social) on 40 years of great tit data from Wytham Woods. The natal-to-adult body mass correlation in this population is high on average (r ≈ 0.7) but appears to vary with temperature, rainfall, and density, particularly during breeding.

(A,B) Illustrative plots of strong versus weak among-individual correlation between nestling mass and adult mass; each point represents an individual and the grey line is a linear fit shown for visual reference. (C) A schematic correlation reaction norm translating these two scenarios (A,B) onto a correlation-versus-environment axis; the y-axis
tracks how consistently natal body mass predicts adult mass. Curve shape is illustrative, and does not represent real data.

Among-individual correlations between nestling mass and adult body mass of great tits from Wytham Woods, UK as functions of (A) adult population density (number of pairs of great tits and blue tits in the breeding year), (B) natal population density (number of pairs of great and blue tits in the hatch year), (C) adult temperature (average daily temperature in ºC during breeding), (D) natal temperature (average daily temperature in ºC during development i.e. 0–15 days post hatching), (E) adult rainfall (average daily rainfall in mm during breeding), (F) natal rainfall (average daily rainfall in mm during development i.e. 0–15 days post hatching); Lines show the posterior median effect sizes; shaded bands show 25–75%, 10–90%, and 5–95% credible intervals. Insets show the posterior distribution of the corresponding slope (point = posterior median; thick bar = 50% CI; thin bar = 90% CI; dashed line = zero).

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Devi Satarkar @devisatarkar.bsky.social · 23/09/2026

Heavier great tit nestlings 🐥 usually end up as heavier adults 🐦. Is this always a strong correlation? Our new preprint shows that the strength of this 'silver-spoon' association shifts continuously with environmental context, and is stronger in harsh conditions! www.biorxiv.org/content/10.6...

14-day old great tit (Parus major) nestling in hand. Bird handled under appropriate BTO licence.

Adult great tit (Parus major) in hand. Bird handled under appropriate BTO licence.

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Devi Satarkar @devisatarkar.bsky.social · 23/09/2026

Why would higher breeding density weaken the correlation? Perhaps resources are constrained for everyone when density is high, so even nestlings who started out heavier can't translate that advantage into higher adult mass. At low density, heavier fledglings can capitalise on abundant resources.

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Devi Satarkar @devisatarkar.bsky.social · 23/09/2026

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Journal of Animal Ecology @animalecology.bsky.social · 22/09/2026

📖 New paper! Early-life environment drives long-term decrease in adult body mass in a wild bird population🌍 🐦‍⬛ 🏔️ 🔎 buff.ly/7Lra4iN

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Patrick Lewin @plewin.bsky.social · 10/09/2026

Excited to share my second published PhD chapter out now in Current Biology! @cellpress.bsky.social 🧵 below but tldr: birds are known to use the magnetic field to navigate. But is magnetism the whole story? We find that an amazing avian navigator doesn’t seem to rely on magnetic cues at all.

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Edward Grey Institute @egioxford.bsky.social · 01/09/2026

Remember the summer heatwaves in the UK in 2026? The late May heatwave was exceptional: an event +4.3 sd above mean - likely to occur only once every few decades under normal conditions. It was also unusual in being early and coinciding with tit breeding season. What consequences did it have? 🧵1/n

Temperature fluctuations in Wytham Woods between 15 May and June 15 for 2023-2026. Orange and green lines represent mean hourly temperatures from 218 temperature loggers in 2026 (orange) and 2023-2025 (green). The grey line and ribbon represent the mean daily temperature ± mean daily temperature range from the Central England Temperature dataset (CET; 1772-2025)

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David López-Idiáquez @davididiaquez.bsky.social · 01/09/2026

New preprint out in @biorxivpreprint.bsky.social with @devisatarkar.bsky.social and @sheldonbirds.bsky.social in which we analyse the effects of this summer's unprecedented and severe #heatwave on tit reproduction and mass. www.biorxiv.org/content/10.6...

biorxiv.org

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David López-Idiáquez @davididiaquez.bsky.social · 31/05/2026

This week has been one of the warmest on record in Oxford. This heatwave has also been recorded by the thermologgers we have in @wythamwoods.bsky.social. The period between 23rd and 28th May has been ~8°C (+2.6 SDs) warmer in 2026 than the same period between 2023 and 2025.

Temperature anomalies in May in Wytham Woods between 2023 and 2026. Each line represents the temperature departure from the 4-year mean each hour. In orange, we can see 2026 temperatures which between the 23rd and 28th of May were 8.11º C higher on average than the mean of the 2023-2025 period (representing a difference of 2.6 standard deviations). Data comes from 8 thermologgers. Thick lines represent the average of these 8 loggers and thin lines temperature from each individual logger.

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Ben Sheldon @sheldonbirds.bsky.social · 08/05/2026

Happy 100th Birthday Sir David! Short clip from a film with Sir David Attenborough featuring @ellafcole.bsky.social explaining research in @wythamwoods.bsky.social into how Great Tits adjust behaviour during incubation to fine-tune hatching date: www.youtube.com/watch?v=lGjL...

youtube.com

How Do Birds Incubate Their Eggs? | Attenborough's Wonder of Eggs | BBC Earth

YouTube video by BBC Earth

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David López-Idiáquez @davididiaquez.bsky.social · 25/04/2026

In our new paper, published yesterday, we use the long-term data set of Wytham Woods to show that great tits have maintained stable temperature at breeding despite the almost 2ºC increase in Spring temperature. w. E. Cole, C. Regan & @sheldonbirds.bsky.social Link -> www.science.org/doi/10.1126/...

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Devi Satarkar @devisatarkar.bsky.social · 22/04/2026

The culmination of @davididiaquez.bsky.social & my ambitious experimental plan, a lot of effort, and a solid reality check from the field. Honestly, this is what we wish we'd had before starting our own experiment. Hope this helps others avoid the same pitfalls! @egioxford.bsky.social

A experimental setup in Wytham Woods with air-activated heatpacks being used to manipulate the temperature inside a woodcrete nestbox containing blue tit nestlings

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Devi Satarkar @devisatarkar.bsky.social · 22/04/2026

We hope our paper is useful as a practical guide for anyone planning a nestbox temperature experiment. It brings together what’s been done before, highlights the details that can really shape results, and offers a reporting framework to make future studies easier to design, compare, and interpret.

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Devi Satarkar @devisatarkar.bsky.social · 22/04/2026

Our pilot experiment also showed how hard it can be to achieve the intended temperature manipulation in the field. Even a small detail like thermologger placement within the nestbox can change the apparent treatment effect dramatically, making both implementation and interpretation tricky.

(A) Thermal image of heated and control nestboxes showing non-uniform heat distribution, with hotspots immediately above three heatpacks and cooler regions higher in the nest; (B) Schematic of four iButton thermologgers at different positions within the nestbox: position 1 (immediately above heatpacks, below moss), position 2 (inside nest material); position 3 (inside nestcup), position 4 (nest rim, nestling height), along with three heatpacks below the nestcup (position 4 was selected for the pilot experiment: shown in pink); (C) Temperature time series comparing heated (red), control (blue) and ambient temperatures outside nestbox (green), measured at position 4 (Trial 1), showing a ΔT of ~2.3°C on average with three heatpacks; (D) Temperature time series comparing heated (red) vs control (blue) treatments, measured at position 1 (Trial 2), showing a ΔT of ~12.4°C on average with three heatpacks; (E) Time series of temperature profiles across all four positions comparing heated (top panel, red gradient) vs control (bottom panel, blue gradient) nestboxes (Trial 3); (F) Estimated marginal means (±95% CI) from Trial 3, showing mean temperatures by position and treatment

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Devi Satarkar @devisatarkar.bsky.social · 22/04/2026

One thing the review makes clear is just how much methods vary across studies: heating/cooling devices, box setups, temperature measurements, and reporting practices all differ, making comparisons difficult and leaving researchers with a confusing range of options when designing experiments 🤷‍♀️

Overview of nestbox temperature manipulation studies in wild birds. (A) Global distribution of the 46 nestbox warming/cooling studies (including our pilot experiment), showing strong clustering in temperate Europe and North America. Colours indicate mean annual temperature (°C) and the size of each point represents the number of studies per location; (B) Proportion of studies conducted at different reproductive stages, from nest building through incubation to the nestling period; (C) Proportion of studies using different types of experimental apparatus for warming (red) and cooling (blue); (D) Taxonomic distribution of studies across 16 cavity nesting bird species, with 30 out of 46 studies focusing on tree swallows (Tachycineta bicolor), great tits (Parus major) and blue tits (Cyanistes caeruleus); (E) Reported temperature differences between experimental and control nestboxes (Δ°C) for heating (red) and cooling (blue) treatments, illustrating the wide range of achieved temperature manipulations; (F) Reported positions within the nestbox where temperature was measured (with number of studies in parentheses), highlighting heterogeneity in measurement location among studies

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Devi Satarkar @devisatarkar.bsky.social · 22/04/2026

Planning a nestbox temperature manipulation experiment in birds? We’ve just published a preprint that may be useful! 🪺🪶 We review 46 studies and also share our own blue tit pilot experiment from Wytham Woods, highlighting some very real practical challenges doi.org/10.32942/X25387

a blue tit peeking into a wooden nestbox

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Richard K Broughton @richardkbroughton.bsky.social · 12/03/2026

Great paper showing impact of extreme spring weather on woodland birds (in nestboxes). Besides rain/cold affecting nestling growth, in natural cavities another major impact of extreme weather is the nest hole soaking with rainwater, which can be a big killer. Broods even drown in severe downpours.

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Devi Satarkar @devisatarkar.bsky.social · 11/03/2026

My second DPhil paper is out! A nice example of how continuous long-term monitoring of natural populations can be so valuable for understanding impacts of climate change on wild animals 🪶 📍Wytham Woods, Oxfordshire 🌳🪺

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Devi Satarkar @devisatarkar.bsky.social · 11/03/2026

Would not be possible without your help!

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Oxford Biology @biology.ox.ac.uk · 11/03/2026

Climate extremes are on the rise, and early life is extra vulnerable 🌧️ New research led by @devisatarkar.bsky.social reveals that cold snaps and heavy rain can stunt growth and survival prospects in young great tits 👇

bit.ly

Climate extremes hinder early development in young birds

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David López-Idiáquez @davididiaquez.bsky.social · 15/02/2026

We have published a new pre-print showing a decline in great tit adult and nestling mass of around 1 gram in 47 y. [rate of approx. -0.040 Hadanes] With @ellafcole.bsky.social, @devisatarkar.bsky.social, Sam. Crofts, @mcmahok.bsky.social & @sheldonbirds.bsky.social www.biorxiv.org/content/10.6...

Decline in body mass in adult (left) and nestling great tits. In the nestling plot, the purple line represents all nestling and the green line those that recruited to the population as breeders. Their different slope suggest an increase in the strength of selection on nestling mass something confirmed in the MS by analysing the temporal trends in selection differentials (see link for further information)

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Eleanor Bath @eleanorbath.bsky.social · 11/11/2025

Interested in fighting, flies, and evolution? I've got a project at Durham investigating the ecology, evolution, and genetics of aggression in fruit flies (Drosophila): iapetus.ac.uk/studentships.... All questions welcome - just shoot me a message or email!

iapetus.ac.uk

What drives aggression? Linking Ecology, Evolution, and Genes

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Ben Sheldon @sheldonbirds.bsky.social · 20/10/2025

Interested in a PhD in ornithology? Funding available for projects at the interface of ecology, behaviour & evolution from Oct '26 working on long-term population studies of tits at Wytham, based in @biology.ox.ac.uk in the new Life & Mind Building in Oxford www.findaphd.com/phds/project...

Celebrating a successful field season with great food & good company - May 2025

Front view of the Life & Mind Building, which opened in Oct 2025: The new home of Biology at Oxford

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Devi Satarkar @devisatarkar.bsky.social · 14/10/2025

Our study offers crucial insights into how wild populations may fare amid ongoing climate change, revealing how life history trajectories are shaped by interacting climate stressors and prevailing environmental conditions. Highly relevant as extreme events increase in frequency and intensity! ⛈️ ❄️ 🔥

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Devi Satarkar @devisatarkar.bsky.social · 14/10/2025

Combined effects can worsen outcomes! When chicks face extreme heat + heavy rain, their mass at fledging can reduce dramatically (up to 27% 🔥). Timing is also important. Late broods within a season are predicted to suffer the most, fledging up to 35% lighter under extreme heat and rain ⛈️

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Devi Satarkar @devisatarkar.bsky.social · 14/10/2025

We show that cold snaps hit young hatchlings hardest, while older nestlings are more affected by extreme rain and heat — likely because these conditions indirectly influence the abundance and activity of caterpillars, the great tit’s main food source 🐛

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Devi Satarkar @devisatarkar.bsky.social · 14/10/2025

New preprint! 🪶 We analysed 60 years of data on 83,000+ great tits to show how extreme climate impacts on nestling growth and survival are stage-specific and context-dependent 🐣 🌍🔥❄️ With @davididiaquez.bsky.social @iremsepil.bsky.social @sheldonbirds.bsky.social www.biorxiv.org/content/10.1...

a 14 day old great tit nestling, ringed for individual identification

Figure from the paper showing that extreme climatic events interact with ambient climatic conditions and breeding timing within a season, in a developmental stage-specific manner, to influence nestling growth in great tits

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Delphine De Moor @delphinedemoor.bsky.social · 27/08/2025

@devisatarkar.bsky.social gave beautiful talk on the extent to which social network traits are heritable vs. shaped by the spatial & social environment at birth using long-term data on blue tits 🐣🧬 @behaviour2025.bsky.social @asab.org

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Oxford Biology @biology.ox.ac.uk · 30/07/2025

Wild great tits signal ‘divorce’ long before the breeding season — even in the winter, months before the couples rebreed with different partners in the following spring New study with @universityofleeds.bsky.social in @royalsocietypublishing.org 👇 bit.ly/4lRt7TN @sheldonbirds.bsky.social

bit.ly

Great tits show early signs of splitting up: researchers uncover social clues to bird 'divorce'

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Oxford Biology @biology.ox.ac.uk · 30/01/2025

New research shows that the early-life environment of great tits shapes their adult behaviour more than their genetics 🐦🍃. Read more here ⬇️ bit.ly/40SkDDT @devisatarkar.bsky.social, @sheldonbirds.bsky.social, @iremsepil.bsky.social 📷 @davididiaquez.bsky.social

Great tit at Bagley Woods by David López Idiáquez, Postdoctoral Researcher, University of Oxford.

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Ben Sheldon @sheldonbirds.bsky.social · 07/01/2025

Lovely to see Devi Satarkar’s first DPhil paper out in print

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Devi Satarkar @devisatarkar.bsky.social · 19/07/2024

Had such a wonderful time at #ECBB2024 where I had the privilege of presenting my PhD work at an international conference for the first time ever! Beautiful city & campus and absolutely brilliant people & research 🤩 Thanks to everyone for being so encouraging about my work 🐣

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Devi Satarkar @devisatarkar.bsky.social · 17/07/2024

Excited to share the first preprint from my PhD doi.org/10.1101/2024.07.11.603055 Turns out social phenotypes are not heritable in great tits! Presenting this at #ECBB2024 tomorrow (10 am, Meerkat room). Please come along if you like social networks and birds!...

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Devi Satarkar @devisatarkar.bsky.social · 01/03/2024

Presented my first ever poster at the @royalsociety conference on age and sociality this week and immensely enjoyed 2 days of really cool research and chatting with even cooler people 🤩 Massive thanks to the organisers for such an enlightening meeting ✨

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Devi Satarkar @devisatarkar.bsky.social · 29/06/2022

The review also has comprehensive descriptions of the structure and function of the receptor. Along with how it was discovered and how it came to be ✨ There's more about wound healing 🩹 in there too, with a special focus on zebrafish 🐟 research! @FrontCellDevBio

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