Category Archives: Birds

Speaking at Oxford Ornithological Society – 11th September

Later this month I’ve been invited by the Oxford Ornithological Society to give a talk about my new book Birds & Flowers: An Intimate 50 Million Year Relationship. The talk will summarise the main themes from the book, particularly the sheer diversity of birds that can act as pollinators, what it means for the ecology and evolution of flowers, why the conservation of such interactions matters, and the cultural significance of bird-flower interactions. I’ll also deal with the question of why Europe is so odd when it comes to the question of birds as pollinators.

The talk is on Wednesday 11th September at Exeter Hall, Kidlington, starting at 7.45 pm; it’s free to society members, and non-members are invited to make a donation. Do come along if you’re in the area!

More details here: https://www.oos.org.uk/programme.php

I’ll bring a few copies of Birds & Flowers and Pollinators & Pollination: Nature and Society if anyone wants to buy a signed book.

Also in the diary are talks at South Leicester Birdwatchers (13th November) and Northamptonshire Bird Club (5th March).

If you represent a birding club or natural history society and wish to book me for a talk, please get in touch via my Contact page.

Urban bees are often early bees says a new study

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The latest paper from Muzafar Sirohi‘s PhD work on urban solitary bees has just been published in the journal Zoodiversity, a publication of the National Academy of Sciences of Ukraine. In this paper we looked at how the flight periods of urban populations of bees differ from those in surrounding nature reserves and other “natural” settings. One of the most interesting findings is that urban bees tend to emerge earlier, and be active longer, than their rural counterparts. The quote the study:

“We observed a substantial effect of urban microclimate on bee flight periods. A total of 153 individuals of nine bee species were recorded one to nine weeks before or after their expected flight periods. In contrast, only 14 individuals of four species were seen at unusual flight periods in nature sites.”

In my book Pollinators & Pollination: Nature and Society I discussed the importance of towns and cities for supporting pollinator populations, and conversely how important those populations are for urban food production. Likewise, in Birds and Flowers: An Intimate 50 Million Year Relationship I have a chapter entitled “Urban flowers for urban birds”. The relationship between our built environment and pollinators is a fascinating topic, but there’s still much we don’t understand about how these insects and vertebrates respond behaviorally to urbanisation. Are they adapting in an evolutionary sense, or simply responding flexibly to the different conditions that cities impose on their biologies? Will future climate change make towns and cities uninhabitable for these animals? Hopefully our paper will stimulate further work on these and other topics.

Here’s the full reference with a link to the paper (which is open access):

Sirohi, M. H., Jackson, J., & Ollerton, J. (2024). Comparison of Flight Periods of Solitary and Primitively Eusocial Bees in Urban Environments and Nature Conservation Areas: a Preliminary Report. Zoodiversity 58: 317-334

Here’s the abstract:

Solitary and primitively eusocial bees, an important group of pollinators, have declined in the past few decades. In view of the recent focus on safeguarding pollinating insects, it is vital to understand the basic ecology of species for their conservation, for example their phenologies. We observed the flight periods of solitary and primitively eusocial bees in both the urban core of a large British town and nearby nature conservation areas. The bee surveys were conducted with standardised methods, on warm sunny days from the first appearance of bees in March 2012 and continued until October 2012. This study confirmed that a high number of species are active in the spring season. The emergence dates of species in urban areas and nature sites varied; about 26 of the 35 species were recorded at least one week earlier in urban areas; in contrast, only four species were seen earlier in nature conservation sites. When comparing this with the expected flight periods recorded (largely in nature sites) in the literature, many species were recorded at their expected time. However, a few individuals were recorded after their usual flight activity time, suggesting that the populations were possibly affected by the microclimate in urban areas. More urban phenological data are needed to understand the phenological trends in bees in urban habitats.

Pollination by birds: the curious case of Europe

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Earlier this year I was invited by the editor of British Wildlife magazine to write a piece for their Changing Perspectives section about how odd Europe is when it comes to bird pollination. It’s based on one of the chapters in my book Birds & Flowers: An Intimate 50 Million Year Relationship.

If you subscribe to the magazine, it will appear in the August issue, though I’m happy to send a PDF to anyone who doesn’t subscribe (or has not read the book) – use the Contact Page. The main accompanying photograph is by one of my former students, Lisa King, who kindly allowed me to use it.

If osiers are all you know – China Diary 6

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It’s very easy to get a fixed idea of what you think a particular group of plants ‘ought’ to look like, based on those that are most familiar to you from where you live. But exploring a good botanic garden always reveals surprises, as far as plant families are concerned. Willows (or osiers) provided me with a great example recently. Based on those that I am familiar with, I thought I had a pretty good idea of what to expect from the family Salicaceae, which includes not just willows (Salix spp.) but also aspens and poplars.

Then you encounter the trunk of a large tree that’s covered in vicious thorns that remind you of the rose family (Rosaceae) and particularly some species of cherries and plums, such as Blackthorn (Prunus spinosa). But it’s a big tree, larger than expected for that group, and the bark in particular doesn’t look right:

Fortunately, being a botanic garden, there’s a helpful label:

Lo and behold, it’s a member of the willow family! A species of Xylosma, quite a large genus of about 100 species, but not one with which I am familiar.

I encountered another example in the Chinese medicinal garden – a species of milkwort (Polygala). The milkworts that are native to Britain are low-growing, herbaceous species, not tall woody shrubs like this P. arillata. The rather legume-like flowers are familiar, but not displayed in these pendant inflorescences, laburnum style:

This wasn’t the biggest surprise of my China trip so far, however – how about these clusters of yellow-ish white, highly fragrant flowers, on a large (15 metre) tree? What family could it belong to?

Again, Rosaceae comes to mind, but it turns out that it’s in the borage or forget-me-not family (Boraginaceae):

Those last two species are a nice example of a general trends in plant families and genera, which often contain smaller, herbaceous species in cooler, more temperate parts of the world and larger, woody species at lower latitudes in the tropics and subtropics. Bamboos (which are of course woody grasses) are a good example – and we have encountered some spectacular specimens in the garden:

Of course there’s also some familiar species, including birds: how many Little Egrets can you spot in this picture?

Exploring botanic gardens are one of my favourite pastimes, it’s always worthwhile and, in the words of an old blog post of mine, Je ne egret rien.

Listen to my interview on the Crime Pays But Botany Doesn’t podcast!

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Last week I had the pleasure of chatting for over two hours with Joey Santore for his Crime Pays But Botany Doesn’t podcast series about my two books Plants & Pollinators: Nature and Society and Birds & Flowers: An Intimate 50 Million Year Relationship.

I’m a long-standing fan of his YouTube video channel which Joey describes as “A Low-Brow, Crass Approach to Plant Ecology & Evolution as muttered by a Misanthropic Chicago Italian.”

It was a lot of fun to talk flowers and pollinators with him and although I tried to keep my swearing to a minimum, if you know Joey and his work, you know what you’re in for, so be warned! It’s not for the easily offended.

We had sound issues at a couple of points and note that at 54:20 I made an error, and said “hummingbirds” a couple of times when I meant “sunbirds”. Put it down to a lack of coffee that morning….

Here’s the link:

The mystery of what pollinates poinsettias – China Diary 3

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Is it too early to talk about Christmas? Not if you’re interested in pollinators and pollination! The mid-winter festival has featured quite a number of times on my blog over the years, especially in relation to the iconic plants that represent this time of year in Northern Europe, and what one might describe as the ‘cultural biodiversity‘ of Christmas. The final plant that I included in that last post was the poinsettia (Euphorbia pulcherrima) – this is how I described it:

In many ways this is an unusual plant to have such a strong cultural association with Christmas: it’s a mildly toxic species of spurge from tropical Mexico that was introduced to North America in the 19th century, then subsequently to Europe. However its festive connotations date back to the earliest period of Spanish colonisation in the 16th century, so it’s older than some…other Christmasy traditions…

I also discuss poinsettia, and specifically its pollination, in my recent book Birds & Flowers: An Intimate 50 Million Year Relationship – this is what I say in the chapter called ‘Urban flowers for urban birds’:

Just occasionally one sees a bird-pollinated tree planted in a city. The most common in my experience are various banksias in Australia, and the Royal Poinciana (from Madagascar) and the African Tulip Tree in the urban tropics and subtropics elsewhere in the world. I’ve also occasionally encountered large specimens of Poinsettia: when they are given free rein they are a much more impressive plant than their Christmas cousins. The vivid red bracts that surround the clusters of flowers suggest that they may be hummingbird-pollinated in their native Central America, but as far as I know their pollination ecology has not been studied.

Here at the Kunming Botanic Garden there’s several quite large specimens of poinsettia that, as I write, are in full flower, their red bracts a signal to pollinators that can be seen for quite a distance. However we’ve not seen any of the local sunbirds or white-eyes visit the flowers, and, as I said in the book, as far as I know the pollination ecology of poinsettia has never been studied in the wild. Close inspection of the flowers in the garden revealed that almost all of the nectaries had at least one nectar-collecting ant sticking out from it, their prominent backsides a deterrent to the Asian Honey Bees (Apis cerana) that also wanted a piece of the action.

Based on the position of the nectaries in relation to the stamens, if the plant is hummingbird-pollinated then the pollen is likely to end up under the chin of the bird. That’s certainly been described in other plant-bird pollination systems. But it does not have to be birds that move the pollen around – red flowers are also associated with other kinds of pollinators, for example butterflies and beetles. But until someone in Mexico does the necessary field work, we’ll just have to speculate.

A new review of ‘Birds & Flowers’ in the Journal of Pollination Ecology

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The reviews of Birds & Flowers: An Intimate 50 Million Year Relationship are starting to appear in blogs, magazines and journals. The latest, by Diane Campbell, has just been published in the Journal of Pollination Ecology and I’m so pleased that it was positive! I’ve only met Diane a couple of times at conferences but I have a lot of respect for her work. The review is fair and balanced, and gratifyingly enthusiastic, for example:

In this delightful book, [Ollerton] describes the ways that birds and flowers interact. As in his previous book, Pollinators & Pollination: Nature and Society, [he] takes a deeply personal approach to the subject. He combines anecdotes from his research travels around the world, to mountains of Kenya and Tanzania, the Andes of Peru, Brazil, and Nepal, among other places, with his contributions to, and masterful knowledge of, the recent literature…

The review is free to read and download from Journal of Pollination Ecology. I’m so glad that people are enjoying the book – if you’ve bought or borrowed a copy, please do leave a comment and let me know what you think.

The flower that’s pollinated by birds, bees….and the wind!

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In my new book Birds & Flowers: An Intimate 50 Million Year Relationship I spend a bit of time discussing the idea of the bird pollination syndrome that we refer to as ‘ornithophily’, its limitations, and the fact that it has two distinct meanings that are often conflated. One of the problems with ornithophily, and indeed all of the syndromes, is that historically it’s sometimes blinkered scientists to the extent that they only look at the flower visitors that are “right” for the syndrome, ignoring the rest or dismissing them as “secondary pollinators”, a term I dislike.

Why do I dislike that term? Because it fails to capture the complexity of flower-pollinator interactions and relegates an important component of plant reproduction to a subsidiary role. I could go on about this at some length, but if you’re interested in discovering more, look at pages 62-65 of Birds & Flowers. There I contrast the classical Most Effective Pollinator Principle with the equally valid (but much less well studied) Least Effective Pollinator Principle, with a segue into one of my favourite tracks from Led Zeppelin’s second album: What is and What Should Never Be.

But back to the real subject of this post – a flower that corresponds to the classical bird pollination syndrome BUT is also pollinated by bees and (very surprisingly) wind! It’s such an interesting paper by Brazilian ecologists Amanda Pacheco, Pedro Bergamo & Leandro Freitas – here’s the reference and a link to the study:

Pacheco, A., Bergamo, P.J. & Freitas, L. (2024) An unexpected case of wind pollination: ambophily in an ornithophilous tropical mountaintop Orobanchaceae. Plant Systematics and Evolution 310, 9. https://doi.org/10.1007/s00606-024-01890-6

For over 100 years the classical pollination syndromes have acted as a framework for understanding the ecology and evolution of plant-pollinator interactions. But we’ve long known that while they can be a useful shorthand, they do not fully reflect the complexity of how pollination systems evolve. That shouldn’t surprise us because, as I point out in my two recent books, we have data (of any quality) on no more than 10% of the 350,000 or so species of flowering plants!

In addition, those plants for which we do have good data are NOT a random subset of the flowering plants: they have been specifically chosen by researchers because they look to be good systems with which to address particular ecological or evolutionary questions.

Which is fine, but we MUST recognise that this imposes significant restrictions on our understanding of the biodiversity of plant-pollinator interactions. The authors of this paper expressed it very well when they wrote that assumptions about:

“predictability may cause researchers to take for granted that only birds pollinate ornithophilous flowers, hindering research on the contribution of other vectors.”

To which I’d add: it also hinders our understanding of how these interactions evolve over long time scales and across multiple populations.

An obvious question is: how frequent are these sorts of complex pollination systems, involving different pollen vectors of an apparently specialised flower? The answer is that we simply don’t know, because most researchers would have not gone into this level of detail. So a huge congratulations to the authors for a great study – I hope it stimulates others to look beyond the ‘expected’ pollinators of flowers.

Photos: Nathália Susin Streher from the original paper.

Adaptable Elder – and a nice review of my book by Mark Avery!

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One of the many things that I love about Common Elder (Sambucus nigra), and which I didn’t have space to properly convey in my article about the species last year, is just how adaptable it is as a species. The tree possesses a lot of what biologists term “phenotypic plasticity“. This is the ability of an organism to flexibly change aspects of its morphology or behaviour or physiology in response to differences in the environment. Plants are especially good at this because, if they find themselves growing in less-than-optimal conditions, they can’t just uproot themselves and leave for pastures new. This is obvious to anyone who has seen a houseplant struggling in a dark corner of a room: the poor plant will etiolate and bend as its yellowing foliage tries to reach the light from a distant window. The same plant grown on a sunny windowsill will be more compact, greener, and healthier.

When it comes to Elder, and indeed other trees, winter is often the best time to see this plasticity, when the trunks and boughs are not cloaked in greenery. On a coastal walk at Klintebjerg yesterday, I spotted three rather different phenotypes of Common Elder which nicely illustrate this environmental context dependency.

The first was a wind-tortured tree growing at the base of a low hill, directly in the teeth of the prevailing Kattegat weather, its trunk bent away from the sea and its branches lopsidedly pruned:

The second was a more fortunate specimen, growing in the lee of that same hill and allowed to spread its symmetrical arms, as though waiting to embrace any passing birds. It had clearly never been pruned back by the landowner, who had allowed it to grow as a fine, single-trunked small tree:

As we walked back down the hill via a narrow path, enclosed and over-topped by a fairy tale canopy of dense, twisted Blackthorn (Prunus spinosa), I spotted another phenotype, different again. I initially thought that they were the stems of a woody climber, perhaps Old Man’s Beard (Clematis vitalba) or European Honeysuckle (Lonicera periclymenum). When I looked closer it was clear that these were Elder, growing narrow and long, using the Blackthorn as support, as they struggled to reach up through the canopy to gain the light:

There were several individuals like this, presumably the result of seed dispersal by birds perched within the Blackthorn. I don’t think that I’ve ever seen Elder growing in quite this way before, but then how often do we get to peer deeply into the secrets hidden within a dense Blackthorn patch?

I had only planned to write about Common Elder today, but I can’t resist mentioning that, over on his blog, ornithologist Mark Avery has written a very nice review of Birds & Flowers: An Intimate 50 Million Year Relationship. He describes my book as having:

…a lightness of touch and tone that should not be taken for lightness of understanding….This is a fine example of a book which is pitched to increase the public understanding of ecology and evolution, and succeeds.

Thank you Mark, that’s very gratifying to read, and I’m glad that you enjoyed it!

Read my author interview and get a 25% discount off ‘Birds & Flowers’, ‘Pollinators & Pollination’ and other books from Pelagic Publishing!

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I recently did a short interview with Pelagic Publishing’s marketing person, Sarah Stott, which you can read here: https://pelagicpublishing.com/blogs/news/birds-and-flowers-author-interview.

On that page you can sign up to Pelagic’s newsletter (which I STRONGLY recommend, because they produce some great natural history and science books, and not just mine!) and by doing so you can receive a 25% discount on all orders.

What are you waiting for?