Category Archives: Birds

Ivy binds the landscape and bridges the seasons: a new article just published

If you check out the latest issue of Bees and Other Pollinators Quarterly you’ll see that, as well as having a piece on the forthcoming COP26 climate change meeting and what it means for pollinators, the magazine has also published a short opinion piece by me called “In Praise of….Ivy”. The magazine is currently in the shops or you can subscribe by following this link:

Although it can be invasive and an environmental nuisance in parts of the world where it’s introduced, common or European ivy (Hedera helix) is clearly one of the most vital plants across its native range of Europe, southern Scandinavia and the Mediterranean. Its clinging stems bind the landscape and provide habitat for a diversity of creatures. By offering nectar at a time when there’s few other plants in flower, and berries at a crucial point in the winter, ivy bridges a food gap for both nectar feeding insect and fruit eating birds and mammals.

Ivy is a very popular subject for student research because it’s in flower at the start of the university academic year. In the past I’ve had several students carry out their final year projects using ivy to test ideas about pollinator effectiveness and plant reproductive success. Because the open, densely-clustered flowers can dust pollen onto any insect that visits, the most effective pollinators will vary depending on which are abundant at any time and place, and include various types of flies and bees, plus those much-misunderstood wasps!

Perhaps we should leave the final word on ivy to the Northamptonshire ‘Peasant Poet’ John Clare who wrote ‘To the Ivy’ in the early 19th century:

Dark creeping Ivy, with thy berries brown,

That fondly twists’ on ruins all thine own,

Old spire-points studding with a leafy crown

Which every minute threatens to dethrone;

With fearful eye I view thy height sublime,

And oft with quicker step retreat from thence

Where thou, in weak defiance, striv’st with Time,

And holdst his weapons in a dread suspense.

But, bloom of ruins, thou art dear to me,

When, far from danger’s way, thy gloomy pride

Wreathes picturesque around some ancient tree

That bows his branches by some fountain-side:

Then sweet it is from summer suns to be,

With thy green darkness overshadowing me.

Further reading

Bradbury, K. (2015) English ivy: berry good for birds.

Bumblebee Conservation Trust (2021) Ivy mining bee:

Jacobs, J.H., Clark, S.J., Denholm, I., Goulson D., Stoate, C. & Osborne J.L. (2010) Pollinator effectiveness and fruit set in common ivy, Hedera helix (Araliaceae). Arthropod-Plant Interactions 4: 19–28

Ollerton, J. (2021) Pollinators & Pollination: Nature and Society. Pelagic Publishing, Exeter, UK

Ollerton, J., Killick, A., Lamborn, E., Watts, S. & Whiston, M. (2007) Multiple meanings and modes: on the many ways to be a generalist flower. Taxon 56: 717-728

Woodland Trust (2021) Ivy.

Birding in Denmark: my first visit to the Hov Vig Reserve

As well as working on a variety of writing and research projects, Karin and I have spent the last few weeks getting out and about in the Odsherred region of Denmark, exploring the culture and ecology of our new home. Not far from where we are living is the Hov Vig bird reserve which I’d put off visiting until last weekend when my friend and colleague Bo Dalsgaard was due to come and stay with us. Bo is primarily an ornithologist (we’ve collaborated on quite a few hummingbird-flower network studies), so it was going to be a good opportunity to get to know more about the birds of this part of the world.

After an early breakfast we set out for Hog Vig and I have to say that I was extremely impressed by the reserve. As you can see from the map below it’s been created by installing a low causeway across a bay in the fjord, resulting in a shallow, brackish lagoon that is absolutely teeming with bird life! Shallow lagoons like this are very productive, with lots of invertebrates and plants on which the birds can feed.

You can see the start of the causeway on the middle left of this photo:

I hadn’t realised just how shallow the lagoon was until I spotted a Great White Egret wading across the centre, the water barely reaching the middle of its legs. In all we counted 8 of these egrets, though a local birder we encountered told us he’d seen 14 that day. Interestingly, Little Egrets are considered quite uncommon here, a reverse of the situation in the UK.

Although the total area of the reserve, including woodland, is only 334 ha, an extraordinary 267 species of birds have been recorded there:

On the reserve itself we identified 39 species, and a handful more when we visited the nearby coast. Including those that we were unsure of we had just over 50 species, not bad for a day of birding. As well as the egrets, particular highlights were huge numbers of Teal, on the water, large active flocks of Golden Plovers and Lapwings set into motion by a hunting Sparrowhawk, and Bar-tailed Godwits, Stonechats and Eiders.

The most exciting birds for us, however, was a pair of White-tailed Sea Eagles that descended onto one of the low islands in the lagoon to feed on a dead cormorant! The locals describe these birds as ‘flying doors’, very apt given their huge wingspans. Needless to say, their appearance also sent much of the bird life into the air. Here’s a poor photo taken with my camera through Bo’s telescope:

And here are two very happy birders!

Global effects of land-use intensity on pollinator biodiversity: a new study just published

Humans affect the land on which they live in many different ways, and this in turn influences local biodiversity. Sometimes this has positive effects on local wildlife: consider the diversity of birds to be found in well-managed suburban gardens, for example. But often the effect is negative, especially when the land is intensively managed or habitats are destroyed, for example via deforestation or urban development.

This is not a new phenomenon – according to a recent study, most of the habitable parts of the planet have been shaped by humans for at least 12,000 years (see Ellis et al. 2021). What is new, however, is the scale and the speed with which land-use is changing, which are far greater than they have been historically. An important question is the extent to which this change in land-use intensity is affecting pollinator diversity in different parts of the world. Over the past 18 months I’ve been collaborating on a project led by Joe Millard (as part of his PhD) and Tim Newbold which uses the Projecting Responses of Ecological Diversity In Changing Terrestrial Systems (PREDICTS) database to address that very question.

A paper from that collaboration is published today in the journal Nature Communications; it’s open access and can be downloaded by following this link.

The study was global in scale and used data from 12,170 sites to assess the affect of land-use intensity on 4502 pollinating species. The findings are really fascinating; highlights include:

  • In comparison to natural vegetation, low levels of land-use intensity can have a positive effect on the diversity of pollinators.
  • For most land categories, greater intensity of land-use results in significant reductions in diversity and abundance of pollinators, however. For example, for urban sites there’s a 43% drop in number of species and a drop in 62% pollinator abundance from the least to the most intensive urban sites.
  • On cropland, strong negative responses of pollinators to increasing intensity are only found in tropical areas, although different taxonomic groups vary in their responses.
  • The latter finding is especially concerning given that: (i) most pollinator diversity is found in the tropics; (ii) the majority of tropical crops are insect pollinated; and (3) tropical agriculture is becoming increasingly intensive and land use is likely to rapidly change in the coming decades.

The full reference for the study, with all authors, is:

Millard, J., Outhwaite, C.L., Kinnersley, R., Freeman, R., Gregory, R.D., Adedoja, O., Gavini, S., Kioko, E., Kuhlmann, M., Ollerton, J., Ren, Z.-X. & Newbold, T. (2021) Global effects of land-use intensity on local pollinator biodiversity. Nature Communications 12, 2902.

Recent pollinator and pollination related research that’s caught my eye

2020-07-30 16.25.26

As I near completion of the copy-editing phase of my forthcoming book it’s frustrating to see all of the great research that’s been produced in recent weeks that I probably won’t be able to cite!  Here’s a few things that caught my eye:

Damon Hall and Dino Martins have a short piece on Human dimensions of insect pollinator conservation in Current Opinion in Insect Science.  My favourite line is: “any call to ‘save the bees’ must be a call to stabilize agriculture”.  Amen to that.

In the journal New Phytologist, Rhiannon Dalrymple and colleagues, including Angela Moles who hosted me during my recent stay in Australia, have a great study entitled Macroecological patterns in flower colour are shaped by both biotic and abiotic factors.  The title pretty much sums it up: in order to fully understand how flowers evolve we need to consider more than just their interactions with pollinators.  It’s another demonstration of how we must look beyond simplistic ideas about pollination syndromes to fully understand the complexities of the relationship between flowering plants and pollinators…..

…..talking of which, again in New Phytologist, Agnes Dellinger asks: Pollination syndromes in the 21st century: where do we stand and where may we go?  It’s an insightful and far-reaching review of a topic that has intrigued me for more than 25 years.  There are still a lot of questions that need to be asked about a conceptual framework that, up until the 1990s, most people in ecology and biology accepted rather uncritically.  One of the main unanswered questions for me is how further study of largely unexplored floras will reveal the existence of new pollination systems/syndromes.  Which leads nicely to….

… amazing paper in Nature this week by Rodrigo Cámara-Leret et al. showing that New Guinea has the world’s richest island flora.  The described flora includes 13,634 plant species, 68% of which are endemic to New Guinea!  And the description of new species each year is not leveling off, there’s still more to be discovered.  A commentary on the paper by Vojtech Novotny and Kenneth Molem sets some wider context to the work, and quite a number of media outlets have covered the story.  Why is this relevant to pollinators and pollination?  Well, we actually know very little about this critical aspect of the ecology of the island: there’s only a handful of published studies of plant-pollinator interactions from New Guinea, mostly focused on figs, bird-flower interactions, and a couple of crops.  For such a biodiverse part of the world that’s a big gap in our understanding.

Finally, James Reilly, Rachael Winfree and colleagues have a paper in Proceedings of the Royal Society series B showing that: Crop production in the USA is frequently limited by a lack of pollinators.  Most significant findings to me were that of the seven crops studied, five of them have their yields limited by lack of pollinators, and that even in areas of highly intensive farming, wild bees provided as much pollination service as honeybees.

That’s a few of the things that I spotted this week; what have you seen that’s excited or intrigued you?  Feel free to comment.


Animal deaths in the Australian bushfires even greater than first feared – and what about the plants?

2019-12-27 15.07.16

Earlier this year I reported on the unprecedented Australian bushfires with some reflections of what I was observing during my time as a Visiting Research Fellow at the University of New South Wales – see: How are the Australian bushfires affecting biodiversity? Australia reflections part 4.   Karin also wrote a piece about the fires, focusing on the human impacts – see: Climate Change Stories From a Nation on Fire.

At the time scientists and the media were suggesting that perhaps half a billion reptiles, mammals and birds had been killed, a figure that provoked a strong public reaction when accompanied by images of fire-scorched koalas.  This was then revised upwards to 1 billion. But it turns out that even a billion is nowhere close to the real number of animal deaths.  A new interim report commissioned by WWF-Australia suggests that just under 3 billion animals were either directly killed or displaced.  Those which were displaced were vulnerable to feral predators such as foxes and cats, or more likely to succumb to starvation. An article in The Guardian about the WWF-Australia report is worth reading – here’s the link.

The actual figure is 2.69 billion individual animals.  Think about that for a moment.  That’s about equivalent the number of people living in India and China combined.  This is the breakdown for the different animal groups that were assessed:

● 143 million mammals
● 2.46 billion reptiles
● 180 million birds
● 51 million frogs

One thing should be immediately apparent: this is not a complete list of the “animals” that have been killed.  A lack of data means that fish, turtles and (crucially) invertebrates such as spiders, bees, beetles, and earthworms, were excluded.  Those invertebrates live at much higher densities than any of the animal groups that were assessed and indeed are the sole or principle food for many of those species.  The number of insects required to support just the insectivorous birds is staggering: globally, birds are estimated to eat 400-500 million tonnes of insects and other arthropods every year.

Even if we were to consider just the larger invertebrates, those bigger than say 0.5 cm in length (which are a minority – most are considerably smaller), then then the true scale of the animal deaths is going to be one or two orders of magnitude higher.  Or possibly more.  Thirty billion, 300 billion, 3 trillion…?  Who knows?  It’s impossible to estimate, we just don’t have enough information about those organisms.

The other major component of wildlife that is missing from the report is the plants.  I know that studies of plant mortality are being undertaken at the moment and it will be important that this is given the same level of publicity as the assessments of animals.

Writing in the foreword of the report, Dermot O’Gorman the CEO of WWF-Australia pointed out that: “It’s hard to think of another event anywhere in the world in living memory that has killed or displaced that many animals. This ranks as one of the worst wildlife disasters in modern history”.

I disagree.  I think it’s THE worst wildlife disaster in terms of the scale of animal losses over such a short period of time.  No doubt deforestation and destruction of grasslands in South America, Asia and Africa has killed more animals and plants.  But that’s over a timescale of decades to hundreds of years.  Australian wildlife was devastated in a matter of months. And no one knows exactly what the 2020-21 fire season will bring.  But I think that we can safely predict further impacts on wildlife – and people.


Get a 30% discount if you pre-order my new book Pollinators & Pollination: Nature and Society


In the next few months my new book Pollinators & Pollination: Nature and Society will be published.  As you can imagine, I’m very excited! The book is currently available to pre-order: you can find full details here at the Pelagic Publishing website.  If you do pre-order it you can claim a 30% discount by using the pre-publication offer code POLLINATOR.

As with my blog, the book is aimed at a very broad audience including the interested public, gardeners, conservationists, and scientists working in the various sub-fields of pollinator and pollination research. The chapter titles are as follows:

Preface and Acknowledgements
1. The importance of pollinators and pollination
2. More than just bees: the diversity of pollinators
3. To be a flower
4. Fidelity and promiscuity in Darwin’s entangled bank
5. The evolution of pollination strategies
6. A matter of time: from daily cycles to climate change
7. Agricultural perspectives
8. Urban environments
9. The significance of gardens
10. Shifting fates of pollinators
11. New bees on the block
12. Managing, restoring and connecting habitats
13. The politics of pollination
14. Studying pollinators and pollination



The other pollinators: some recent videos that don’t focus on bees

The review of the biodiversity of pollinators that I published in 2017 estimated that on average about 18% of animal-pollinated plants within natural communities are specialised on bees. Bees also contribute to the reproduction of many of the plants that have generalist pollination systems, which account for perhaps 50% of plant species on average. But that stills leaves a significant fraction (maybe one third) that are specialised on the “other” pollinators, including flies, beetles, birds, bats, and so forth. There is growing awareness of how important these pollinators are for wild plant and crop pollination, but bees still hog most of the pollinator-related media.

In the last couple of weeks I’ve been sent links to videos that focus on these other pollinators so I thought I’d compile a list that show us something of the true diversity of animals that act as pollen vectors. Please add your own suggestions in the comments:

Elephant shrews, lizards, cockroaches*, crustaceans, and biting midges are covered in this SciShow video (HT Steve Hawkins)

Opossum pollination of a Brazilian plant is featured in this video (HT Felipe Amorim)

Here’s a recorded webinar on bird pollination by Dan Scheiman from Audubon Arkansas

A few videos on bat pollination by Jim Wolfe can be found here and here and here, and this is a short one that’s a supplement to a recent Journal of Applied Ecology paper on cactus pollination by Constance J. Tremlett et al.

The fascinating ecology of skunk cabbage (Symplocarpus foetidus), including fly and possibly beetle pollination, is the topic of this video.

Fly pollination is also highlighted in this short piece by the Natural History Museum, and this one deals with drone flies as managed pollinators for agriculture in New Zealand.


*Watch out for my report on a newly discovered cockroach-pollinated plant….hopefully coming later this year…..

Life between the tides: Australia reflections part 6

2019-12-08 13.35.05

That last post about climate change and politics was a bit heavy, for which I make no apologies.  But there’s always space for something lighter on this blog.  Sometimes it’s nice to reflect on what brought me to the point of being a scientist with an interest in biodiversity.  Some of my earliest exposure to natural history involved peering into rock pools on the coast near Sunderland in the north east of England.  In an old family album there’s a photograph of me aged about four, intently gazing at the welks, crabs and anemones as they wait for the next tidal surge to bring food or predators.  If I wasn’t in Australia I’d go and hunt that photo down and share it with you.  Right into my 20s my dad would tell any and every one about my childhood obsession with “gannin’ on the yocks”.  The word “gannin'” is north eastern colloquial English for “going” while “yocks” was me not being able to pronounce “rocks”.  “I’m gannin’ on the yocks” became a family catchphrase that could be used in any number of circumstances.  It might just sum up my professional career if I think hard about it….

Later, at school and then college, I took part in several class projects that involved running transect lines down the shore and examining the zonation of the creatures: more hardy organisms, predictably, at higher points, the sensitive species lower down.  Generations of biology students must have done similar studies.  Do they still?

These rocky shore reminiscences have been inspired by a great piece of writing about tide pooling by Sarah Jean McPeek over at the Lively Discussions blog.  I can’t match Sarah’s eloquent lyricism but I can match her love of a rocky shore.  There are some great ones on the coast near Coogee, ranging from very small, deep holes, up to huge, artificial ones that were built as ocean swimming pools. Here’s some photos:

2019-12-29 13.36.56

2019-12-08 13.35.11

Holes within a pool.  This is a great opportunity for a rocky shore ecologist to do a replicated manipulation experiment:

2019-12-08 15.21.19

This is a different kind of experiment to test the hypothesis that water in large pools has evaporated enough to make it significantly more saline and thus increase the buoyancy of the human body.  Hypothesis supported:

2019-12-29 13.21.30

2019-12-29 13.28.41

A classic wave-cut platform:

2019-12-15 11.29.49

2019-12-29 13.34.41

This very distinctive seaweed is known as Neptune’s necklace (Hormosira banksii):

2019-12-29 13.34.04

This pool is being influenced by a freshwater spring that’s coming in from the left:

2019-12-29 13.28.45

These fresh water streams and pools are important for the local coastal birds, including silver gulls (Chroicocephalus novaehollandiae) which belong to the same genus as black-headed gulls (C. ridibundus) in the northern hemisphere but which I think is a prettier species:

2019-12-29 14.15.45

2020-01-07 19.46.07

Australian white ibis (Threskiornis molucca) also enjoy the fresh water pools:

2020-01-02 14.21.02

Humans have inhabited this coastal area for at least 20,000 years and its the traditional land of the Cadigal people.  In more recent times the locals have enjoyed the huge tidal swimming pool known as Wylie’s Baths.  I’ve snorkeled here a few times and seen some beautiful fish and invertebrates:

2020-01-04 17.09.02

2020-01-04 17.09.07

2020-01-04 17.09.11

Much further up the coast at Port Macquarie, which we visited over Christmas as I recalled in this post, the geology is very different.  The rocky shores are composed of hard volcanic basalt rather than the softer Sydney sandstone:

2019-12-26 09.56.13

2019-12-24 11.01.32

This is an incredibly dynamic environment.  According to my relatives in Port Macquarie, the place where Karin is standing was until recently a rock pool almost two metres deep that was rapidly filled up by the shifting sands of the coast.  Winter storms will probably scour the sand out again.  Will the limpets and barnacles have survived I wonder?

2019-12-24 11.04.12

2019-12-22 15.24.06




Just published: Interactions between birds and flowers of Rhododendron spp., and their implications for mountain communities in Nepal – download it for free

Figure 3

Back in April I posted a series of reports on a student field trip that I was involved with in Nepal, supporting our University of Northampton partner college NAMI in Kathmandu; the first one is here.  During that trip, my NAMI colleagues and I made some interesting observations about the role of generalist passerine birds and specialist flower-feeding sunbirds as pollinators of rhododendrons in the Himalayas.  This was subsequently followed up with another set of observations in which I didn’t take part, and then written up as a short research note.  I’m pleased to say that it has now been published in the new, open-access journal Plants, People, Planet.  Here’s a link to the paper which you can download for free:

Ollerton J., Koju N.P., Maharjan S.R. & Bashyal B. (2019) Interactions between birds and flowers of Rhododendron spp., and their implications for mountain communities in Nepal. Plants, People, Planet 00:1–6. https ://

The report really asks more questions than it answers.  It points out how important these rhododendron forests are for the people of Nepal but that we know virtually nothing about the pollination biology of the dominant trees and therefore the long-term persistence of Rhododendron species in the face of forest exploitation and climate change.  Our hope is that it stimulates both further research on the topic and increased awareness of how important it is to protect these habitats.

Scoring (real) birdies: Australia reflections part 2

2019-12-18 08.02.28

When it comes to golf I’m largely in agreement with Mark Twain who was reported to have described the game as “a good walk spoiled”.  As with so many of these well known and iconic quotes, Twain did not originate the phrase and almost certainly did not say it.  Reminds me of what Einstein didn’t say about bees.   Regardless of how you feel about golf*, and I appreciate that many people enjoy and play the game, golf courses represent an interesting set of environmental challenges and opportunities.  On the one hand maintaining areas of perfect turf requires a big input of water, fertilisers, biocides, even grass dye, and energy – there are some interesting thoughts on this in a recent blog post at (though it’s riddled with adverts so be patient).  One of the links I picked up from that blog was to the Audubon Society in the USA which has an Audubon Cooperative Sanctuary Program for Golf certification scheme.  Its aim is to help course management teams to reduce the impact of their activities and, importantly, to maximise and protect the biodiversity on their golf courses.

There are similar schemes elsewhere in the world, for example the Golf Environment Awards in the UK.  Of course building new golf courses that irreparably damage important wildlife sites is unforgivable. For existing courses these are moves in the right direction because typically less than half of a course is the playing area.  The rest comprises rough grass, woodland, lakes and streams and so forth: in other words, good habitat for a broad range of wildlife.

2019-12-18 08.00.34

All of this was on my mind last Wednesday when I was invited on an early morning birding trip to the urban Eastlake Golf Course by UNSW bird researcher Dr Corey Callaghan.  We were joined by other staff members and postgrads from the department. Six of us spent a very enjoyable couple of hours from 6:15 am walking a route that took us close to the large bodies of water that give the course its name, through woodland and bush dominated by species of Banksia and Casuarina. The latter, despite being true flowering plants, look for all the world like the familiar conifers of many a British golf course.

Over a period of two hours we saw 70 species of birds.  To put this in perspective, our Waterside Campus bird surveys back in Northampton also take around two hours and start early in the morning, through a similar mosaic of grassland, woodland patches, and a water body (the River Nene).  On these surveys we typically see between 20 and 30 species; the most we’ve ever recorded in one morning is 39, and that really was exceptional.  Remember also that Sydney is not in the tropics – at around 33 degrees south we’re technically subtropical here.  Given the latitudinal gradient in bird diversity, a two hour survey on a tropical golf course should yield even more records, all else being equal.

2019-12-18 07.04.54

Of those 70 bird species, I think about 20 were new to me, i.e. lifers in birding parlance, though I still need to write up the list of birds I’ve seen so far on this trip.  Perhaps I’ll do that this afternoon as temperature in Sydney peak and its frankly too hot to do much else. As I write it’s midday and official temperature for the Coogee area is already 29 degrees C, and that’s with a cooling sea breeze.  Western Sydney is likely to top 40 degree later today.

Although whole families of birds in this region are unfamiliar to us in the Northern Hemisphere, there were others that we saw on Wednesday which would not be out of place in Northamptonshire.  For example, we saw common greenshank, which overwinters here after an epic journey from northern climes, and Australian raven which is a different species to the ravens and crows from the UK, but very similar looking.  The wading birds such as greenshank and sharp-tailed sandpiper were benefiting from the drought conditions that has exposed parts of the lake bed. Though if this continues there’s a danger of most of the water being lost completely, impacting the  large eels and other fish we saw in the shallows, as well as the semi-aquatic Eastern water dragon.

2019-12-18 07.04.59

Birds, plants, fish and lizards were not the only wildlife we saw at Eastlake however – some very delicate fungi were benefiting from the regular watering of the fairway:

2019-12-18 07.35.55

It’s not all been birding and swimming in the (not very) warm sea, however.  This week Angela, Stephen and I were joined by our CSIRO collaborator Dr Raghu Sathyamurthy for an intense week of writing.  This manuscript boot camp has gone better than we expected and we have a very good first draft of a paper that should be in a position to submit to a journal by the time my visit here ends on 2nd February.


*I make an exception for crazy golf at seaside resorts which I play with my old university mates with beer, gusto, and not a little rivalry.