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David López-Idiáquez

@davididiaquez.bsky.social
373 followers 309 following 179 posts

Behavioural and Evolutionary Ecologist at the Edward Grey Institute of Field Ornithology. Expect science, wildlife pictures and bike stuff (but not in that particular order). davididiaquez.wixsite.com/zurrimicle

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David López-Idiáquez @davididiaquez.bsky.social · 12/09/2026
Epic!
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David López-Idiáquez @davididiaquez.bsky.social · 01/09/2026
Overall, the May 2026 heatwave notably worsened seasonal declines in fledgling number and nestling mass, with likely longer-term effects via survival. As such extreme events increase in frequency, these findings may offer an early benchmark for their impacts.
Dead blue tit nestling found after the heatwave in Wytham Woods
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David López-Idiáquez @davididiaquez.bsky.social · 01/09/2026
It exacerbated the well-known seasonal decrease in breeding success that these species experience. In regular years late broods fledge c. 2.6 fewer fledglings than early broods, this difference was almost double in 2026 (c. 4.5 fewer fledglings) and similarly with nestling mass.
Heatwave effects on great and blue tit fledgling number and nestling mass. Dots and whiskers represent predicted mean ± standard deviation values from the models. Pre-heatwave and heatwave represent the relative periods before and after the heatwave (see pre-print SI-1). Orange represents the heatwave year (2026) and green the non-heatwave years (1978-2025). Values within the plot represent the mean change in the dependent variable between periods and its standard error. The p-value denotes the significance of the difference between heatwave and non-heatwave years. Number of fledglings and nestling mass were centred to a mean of zero
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David López-Idiáquez @davididiaquez.bsky.social · 01/09/2026
Wytham Woods, near Oxford, was not immune to this heat spell and mean temperature during the late May heatwave was up to 10.5 ºC higher than the historical average.
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
During late May and early June the UK like most of Europe experienced an unprecedented spell of heat that broke all the previous high temperatures recorded at that time of the year, an meteorological event that had measurable effects on the human population (see: zenodo.org/records/2126...)
Mean daily maximum temperature in the United Kingdom during the 25 and 26 of May between 1931 and 2025, and in 2026. The white dot represents Wytham Woods, near Oxford. Data from HadUK-Grid 1km gridded observational dataset (v.1.3.2)
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David López-Idiáquez @davididiaquez.bsky.social · 12/08/2026
Enjoyed it more than expected!! It’s been pretty cool and special!
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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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David López-Idiáquez @davididiaquez.bsky.social · 09/05/2026
Tit poker!
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David López-Idiáquez @davididiaquez.bsky.social · 09/05/2026
Something different to brighten my day
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David López-Idiáquez @davididiaquez.bsky.social · 05/05/2026
Things are crazy down here already!!
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David López-Idiáquez @davididiaquez.bsky.social · 25/04/2026
This study was only possible thanks to the work of devoted groups of fieldworkers from the @egioxford.bsky.social that have spent their springs chasing tits in @wythamwoods.bsky.social since 1947, when the monitoring of this population started.
2024 cohort of fieldworker in Wytham Woods (c) K. McMahon
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David López-Idiáquez @davididiaquez.bsky.social · 25/04/2026
Our results show a strong link between the temperature experienced by great tits during breeding and mismatch with the phenology of their prey. The temperature that maximised the synchrony with the winter moths tightly aligned with that maximising breeding success.
Relationship between the temperature experienced by each brood at laying and their synchrony with the peak of food availability. 

Lines represent the trends predicted by the model before and after the temperature that minimises mismatch (black dot). Big green dots represent the mean raw abs. mismatch in temperature bins of 1 degree. The small green dot the mean temperature experienced by the tits during laying.

Results from this model were obtained following an approach similar to the figure showing the links between temperature and reproductive success.
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David López-Idiáquez @davididiaquez.bsky.social · 25/04/2026
These results are, thus, consistent with natural selection having acted to enable the temperature tracking.
Links between the temperature experience by each brood at egg-laying (one of the relative periods) and four metrics of breeding success, clutch size (A), number of fledglings (B), fledging success (C) and number of recruits (D).

Lines represent the trends predicted by the models before and after the peak (black dot), and the green big dots mean breeding success in temperature bins of 1 degree ± one standard deviation.

The (small) green and black dots on the top of the each plot represent the temperature that maximised reproductive success (black) and the mean temperature experienced by the population at egg-laying (green).

The temperature value that maximises reproductive success (black dot) of obtained from a model fitting non-linear associations between temperature and breeding success, while the trends after and before this temperature were obtained by fitting linear models between temperature and reproductive success.
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David López-Idiáquez @davididiaquez.bsky.social · 25/04/2026
We used more than 12,000 breeding attempts collected over almost six decades to show that plasticity in reproductive timing has enabled long-term thermal homeostasis. Interestingly, the temperature tracked by the birds closely aligned with that maximising reproductive success in our population.
Plot representing the slopes of the temporal trends in temperature using different time intervals. 

First, the grey dot shows that temperature in Wytham Woods has increased at a rate of ~0.032 degrees per year (1.88 degrees in the whole time series) when using a fixed time interval between the 15th of February and June 5th. 

The coloured dots represent the temperature change in 5 time intervals relative to individual broods corresponding to relevant reproductive stages for the birds (egg-laying, incubation, and the hatching, nestling and fledgling periods of the chicks). 

In those the slopes of temperature change are non-significant and close to 0, showing that temperature in those periods has not shown any significant temporal trends. (For more information see the main text)
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David López-Idiáquez @davididiaquez.bsky.social · 14/03/2026
Not that easy being a toad @wythamwoods.bsky.social
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David López-Idiáquez @davididiaquez.bsky.social · 11/03/2026
Tropical Oxford.
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David López-Idiáquez @davididiaquez.bsky.social · 03/03/2026
I had the chance to handle some a few years ago and they are awesome
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David López-Idiáquez @davididiaquez.bsky.social · 02/03/2026
Counting swans and collecting poo.
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David López-Idiáquez @davididiaquez.bsky.social · 15/02/2026
A more developed analysis of the temporal trends in adults revealed a two level process, akin to Simpson's paradox. While the population level trend is negative, the temporal trends within each tit cohort are positive (likely reflecting an age dependent increase in mass).
Temporal trends in adult great tit body mass showing a decrease in mass at the population level and an increase in mass with year within each cohort
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David López-Idiáquez @davididiaquez.bsky.social · 15/02/2026
The lack of strong associations between adult mass and the environment leave a question open: what does explain the decrease we see in adults?
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David López-Idiáquez @davididiaquez.bsky.social · 15/02/2026
Adult mass was weakly sensitive to the environmental variation. Nestling mass, however, was negatively associated to competition (by great and blue tits), and given that both the number of great and blue tits has increased in Wytham, we think that this explains the trends in reported in nestlings.
Association between nestling mass and great (C) and blue tit numbers (D). The line and ribbon represent the trends predicted by the model and the dots and whiskers the mean ± 1 standard deviation of the raw data in bins of 20 pairs. Density plots represent the distribution of number of blue and great tits in each analysis (and hence give information about the sample size).
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David López-Idiáquez @davididiaquez.bsky.social · 15/02/2026
Quantitative genetic analyses using a pedigree spanning 36 generations revealed that despite an heritability of 37% there was no change in body mass at the genetic level. Therefore, suggesting that the change can be attributed to phenotypic plasticity.
Great tit from Wytham Woods
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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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David López-Idiáquez @davididiaquez.bsky.social · 29/01/2026
Mmm, good question. I think that mine is the view of Port Meadow from the top of Botley Hill (point between Singing way and Marley) at sunrise. When is foggy the view is stunning. I also like a lot the view of the city from the top of South Park.
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David López-Idiáquez @davididiaquez.bsky.social · 28/01/2026
Port Meadow (from Wolvercote) at its best this morning.
Port Meadow from Wolvercote
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David López-Idiáquez @davididiaquez.bsky.social · 06/01/2026
I may be a bit early
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David López-Idiáquez @davididiaquez.bsky.social · 29/12/2025
Recycling this little map I made with my rounds in the Woods this Spring
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David López-Idiáquez @davididiaquez.bsky.social · 29/12/2025
I guess that one could infer the phenology of Wytham great tits by my activity in Strava :-)
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David López-Idiáquez @davididiaquez.bsky.social · 24/12/2025
Not a good year for badgers, I guess.
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David López-Idiáquez @davididiaquez.bsky.social · 20/12/2025
The end product after playing to be a dentist this morning 🦡🦡🦡
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David López-Idiáquez @davididiaquez.bsky.social · 17/12/2025
Wytham gives, david takes.
Skull of a badger found in Wytham woods
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David López-Idiáquez @davididiaquez.bsky.social · 18/11/2025
Nice way to split the week :-)
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David López-Idiáquez @davididiaquez.bsky.social · 23/10/2025
They knew how to put a good title in the old days...
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David López-Idiáquez @davididiaquez.bsky.social · 21/10/2025
Amazing autumn day at the woods helping with some teaching. I missed the ring ouzel that surprised some (well just one) of us, but the colour of the trees was amazing!
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David López-Idiáquez @davididiaquez.bsky.social · 09/10/2025
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David López-Idiáquez @davididiaquez.bsky.social · 09/10/2025
I also found some pictures of not that common nest box dwellers
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David López-Idiáquez @davididiaquez.bsky.social · 09/10/2025
I needed to go through some pictures from the fieldwork I did in Corsica, and in addition to the amazing landscapes
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David López-Idiáquez @davididiaquez.bsky.social · 06/10/2025
Morning ringing in the woods which are turning into autumn colours!
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David López-Idiáquez @davididiaquez.bsky.social · 04/10/2025
Matching habitat choice?
A fox in front of a brick wall in Marston, Oxford
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David López-Idiáquez @davididiaquez.bsky.social · 01/10/2025
Nice morning ringing at Wytham woods
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David López-Idiáquez @davididiaquez.bsky.social · 27/09/2025
I found this mallard today. It seems like some kind of hybrid—if it is, is it possible to identify the species? Or is it just a chromatic aberration?
mallard with a strange colour variation, potentially a hybrid.
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David López-Idiáquez @davididiaquez.bsky.social · 20/09/2025
A blue tit was seen.
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David López-Idiáquez @davididiaquez.bsky.social · 20/09/2025
Nice morning at @rspbotmoor.bsky.social
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David López-Idiáquez @davididiaquez.bsky.social · 12/09/2025
What a nice end for a really nice conference. Lovely time in Olomouc meeting old friends and making new. Really amazing conference @hnbirds2025.bsky.social
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David López-Idiáquez @davididiaquez.bsky.social · 29/08/2025
Alguien me podría ayudar a identificar este pequeño animal multicolor que me he encontrado en el sur de España?
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David López-Idiáquez @davididiaquez.bsky.social · 30/06/2025
La caló
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David López-Idiáquez @davididiaquez.bsky.social · 25/06/2025
Not as close as the one I had in Montpellier, which was literally in the garden
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David López-Idiáquez @davididiaquez.bsky.social · 25/06/2025
Really weak, but it seems that I have a new neighbour:-)
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David López-Idiáquez @davididiaquez.bsky.social · 26/05/2025
The highlight of the season was discovering a marsh tit breeding in a natural cavity.
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David López-Idiáquez @davididiaquez.bsky.social · 26/05/2025
I did this by cycling into the woods, almost 546km with 4500m of elevation gain, not bad for Oxfordshire. This included climbing the infamous Tilbury Lane Climb.
Daily cycling routine during fieldwork
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