Plot showing the cumulative percentage of trees in first budburst and first leaf across the Phenoweb Transect since 1 April 2026. Orange line shows southern sites, while the blue line shows northern sites. The black line represents the transect-wide trend.

Oak budburst.

Sycamore budburst.

Beech budburst.

Spring is gaining momentum across Scotland. 🌱

Cumulative budburst across the transect has now passed 40%, driven by a surge of activity at our northern sites in recent days. While the North is waking up, the South continues to lead the way in terms of first leaf emergence.

#Phenology #Spring2026

One blue tit egg in a cozy looking nest lined with feathers.

Plot showing the first egg date recorded for the project between 2014 and 2026.

The first egg for the 13th year of data collection along the Phenoweb Transect was laid on 12th April 2026! Looking like we’re in for a fairly ‘average‘ year up here in Scotland, with nest building and budburst progressing slightly slower than in 2025, especially in the North of the transect🪺🌳

Figure 1: Winter moth life cycle. Adult winter moths emerge in Novem- ber/December and shortly after mating brachypterous females crawl up trees to lay eggs. Eggs hatch in early spring, and larvae feed on young foliage until late May when they descend to the ground on silken threads to burrow into the soil and pupate. Pupation lasts until winter, when adults emerge and the life cycle begins again. Solid black arrows indi- cate the duration of each development stage and blue dashed arrows indicate the temporal variability of each stage.

Figure 3: The effect of temperature treatment on pupal development time. Each coloured point represents the number of days between the start of the experiment (used as a proxy for pupation date) and the emergence date of an individual adult moth. Horizontal bars indicate treatment means and the dashed vertical line separates the experi- mental treatments from the ambient.

Figure 5: The effect of temperature treatment on egg development time. Each coloured point represents the number of days between the first egg-laying event and half-hatch date of each subclutch. Horizontal bars indicate treatment means and the dashed vertical line separates the experimental treatments from the ambient.

Figure 6: The effect of maternal emergence date on offspring’s egg development time. Points represent subclutches so those aligned in the x-axis are from the same mother. Lines show the model prediction with a 95% confidence interval represented by the shaded ribbon. Both are coloured by egg temperature treatment.

New preprint (part of a programme to understand resilience of the tritrophic tree-insect-bird system to varying climate). We (led by @siennarattigan.bsky.social - her MBiol project) show how temperature in development can carry-over to affect timing at later stages
www.biorxiv.org/content/10.6...

A snowy mountain scene taken in the northern Cairngorms on 5 April 2026.

Woodcrete nest box hanging from a snow-covered tree.

Woodcrete nest box hanging from a tree, with a snowy landscape in the background.

The first week of the 2026 field season is underway, and Storm Dave has provided a chilly – but atmospheric – start. ❄️🏔

63 blue tit nests initiated, so far, with 4 lined. Looking like a later start for us compared to elsewhere in the UK/Western Europe.

#phenology

This research was part of my integraed Masters @biology.ox.ac.uk and was greatly supported by members of @egioxford.bsky.social

📑Our study highlights the need to consider the impacts of warming across multiple life stages so that carryover effects can be properly accounted for. Doing so may improve our ability to predict, and suggest mitigations for, trophic asynchrony under future climates.

Plot showing the effect of maternal emergence date on offspring’s egg development time.

Furthermore, temperature-driven shifts in maternal phenology carried over to offspring, and although some compensation occurred in later stages, this buffering weakened under warmer conditions, potentially compromising winter moth–host tree synchrony under future climates.

Plot showing the effect of temperature treatment on pupal development time.

Plot showing the effect of temperature on egg development time.

We found divergent effects of temperature on different life stages; pupal development time was shortest at intermediate temperatures while egg development time decreased linearly with increasing temperature.

Winter moth lifecycle with solid black arrows indicating the duration of each developmental stage and blue dashed arrows indicating the temporal variability of each stage.

Male (left) and female (right) winter moths in the lab.

We used an experimental approach, involving temperature regimes derived from 50 years of local climate date, to investigate how temperature experienced the previous autumn and winter (during the pupal and egg stage) influences spring phenology in the winter moth (Operophtera brumata).

1/🧵My first preprint!🐛🌡️

We examine how environmental effects experienced during one life-history stage persist and modulate environmental responses in later life-history stages.

With Lea Beaupere, @sheldonbirds.bsky.social, @rona-learmonth.bsky.social

www.biorxiv.org/content/10.6...

Fieldworker kneeling on the ground helping to install the Soprano device as it snows.

Two Soprano devices stood next to each other in the field. They consist of a solar panel, battery, circuit board, audio moth and antenna all mounted onto a tripod.

Ahead of this year’s field season, we’ve been busy installing SOPRANO devices at several of our sites. These devices automatically monitor biodiversity and climate, continuously recording birds and bats and sending real-time species identifications back to Edinburgh!🔈🐦‍⬛🦇

📑📊We have just uploaded a new pre-print where we decompose spatial, temporal and spatial-temporal variation in natural selection on reproductive traits for great tits and blue tits.
With Yimen Araya-Ajoy, @ellafcole.bsky.social and @sheldonbirds.bsky.social
www.biorxiv.org/content/10.6...

Developmental Stage‐Specific Responses to Extreme Climatic Events and Environmental Variability in Great Tit Nestlings Extreme climatic events (ECEs) impact great tit nestlings in a developmental stage-specific and context-dependent manner. Using 60 years of data on 83,000+ great tit nestlings from Wytham Woods, UK, ...

New paper out! Great tits face distinct challenges from extreme weather during development, based on 60 years data from >83k nestlings in Wytham Woods 🐣 Cold snaps & heavy rain can stunt growth, but earlier breeding may help buffer this! By @devisatarkar.bsky.social et al.
doi.org/10.1111/gcb.70794

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)

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...

🚨🚨🚨 Field Assistant positions - four of them!! - working with the long-term Wytham project this coming spring. Details below. Previous year's field team - come and join us! Details below ⬇️

Very excited to be giving a talk at #BES2025 where I’ll be presenting my Masters research that I carried out @biology.ox.ac.uk supervised by @sheldonbirds.bsky.social and @rona-learmonth.bsky.social 🐛🌡️

Project | E5 Doctoral Training Partnership | E5 Doctoral Training Partnership The project advertisement

Second PhD alert:

Advertising a second PhD alongside Amanda Lenzi (lead) and Finn Lindgren on: 'Forecasting nature’s calendar: Joint probabilistic models of phenology in space and time'. Also competition funded through the E5 DTP at Uni of Edinburgh.

e5-dtp.ed.ac.uk/project?item...

alt="Schematic of a graph of a population trajectory for blue tits that is known for half of the x-axis (time) and then forecasted with uncertainty. Above the population trajectory are some weather images (a sun and some rain) they have connections to the population size but the path is unknown. "

PhD advert alert!

Come work with me at Edinburgh.

I'm advertising a PhD on: "Predicting responses of birds to climate change", competition funded through the E5 DTP. Would suit those with an interest in predicting responses to climate change, birds, or both.

e5-dtp.ed.ac.uk/project?item...

Examples of some recent papers from graduate students in my group - a full list of recent papers and preprints can be found here (https://scholar.google.co.uk/citations?hl=en&user=pTdxVdIAAAAJ) and profile of the group here: https://egioxford.web.ox.ac.uk/members

The annual Wytham Field Team Photo!

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

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...

Integrative analysis of fine-scale local adaptation of winter moths to variable oak phenology For herbivorous insects whose fitness depends on tight phenological synchrony with host plants, spatial variation in plant phenology can impose strong selective pressures and promote local adaptation ...

New preprint! 🌳🐛

We combined experimental and genomic methods to study local adaptation of winter moths to variation in oak budburst timing in Wytham Woods, UK.

With @andreaestandia.bsky.social, Lea Beaupere, Ella Cole, and @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

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...

My first time attending this conference, but certainly not the last! Left me feeling super excited to started my PhD in October after hearing so many incredible talks in the field🪺

🔭🐑 Our summer field team have been busy beavering away and have completed their 10 censuses of the village bay population (picured). Over ten days a team of three will go out and count all the sheep in this area, tagged and untagged, so we know who is where and who they are grouping with.

Global patterns of colouration complexity in the Paridae: Effects of climate and species characteristics across body regions Variation in colour complexity in the Paridae is linked to climate, climate variability and several biotic factors. The strength of the associations is patch specific. Variables related to resource c...

Happy to share our last work just published in @animalecology.bsky.social. With @claire-doutrelant.bsky.social and Peter Pearman. besjournals.onlinelibrary.wiley.com/doi/10.1111/... @cnrs.fr @biology.ox.ac.uk

Feel incredibly lucky to have been a tiny cog in this amazing team for a second year now. I don’t think i’ll ever get tired of seeing spring unfold right before my eyes! Excited to do it all again next year when I’ll be a bit further north… @phenoweb.bsky.social 🪺

Meanwhile my 'baby' nest round required cycling a mere 210km with only 1050m of elevation gain... I can't compete, its no wonder you're the strava local legend!

A single Blue Tit egg in a complete nest inside a woodcrete nestbox in Wytham Woods, 3 April 2025

Early developing Oak in Wytham Woods, Oxfordshire, April 2025

Newly emerged Oak leaves, Wytham Woods, near Oxford, 3 April 2025

Figures showing the change in the date of the first egg in the Great Tit and Blue Tit populations at Wytham Woods, near Oxford 1960-2025, and the relationship between average March daily maximum temperature and date of the first egg in the population for each species. In each figure the line fitted is for the data for the 65 years from 1960-2024, with the value for 2025 shown as a green (Great Tit) or blue (Blue Tit) star. The two right hand panels compare the change over time and the response to March temperature in the two species; Great Tits show a slightly steeper response to temperature than Blue Tits, and are advancing the population first egg date slightly more quickly.

The first eggs have been laid in this, the 79th year of data collection in the Wytham Tit Project! First Blue Tit egg laid 2 April, first Great Tit 3 April. Looks like an early spring, with first oak leaves out, though the observed first egg dates fit the long-term pattern well
wythamtits.com#intro