The birds and the bees = berries!

December 3, 2012

in Birds, Bumblebees and their ecology

“All my articles and videos, available free, are funded by my  teaching and sales of award winning bumblebee nest boxessolitary bee boxes,  and wormeries. Please help by spreading the word and forwarding this link to your friends and colleagues. http://nurturing-nature.co.uk  Thank you” George Pilkington

Birds and berries need bees

Blue tit eating hawthorn berry pulp

 

The British Trust for Ornithology, (BTO) as part of their Garden Birdwatch scheme, are undertaking a new observational study called “Bird and Garden Berries Study”. They wish to increase their knowledge and understanding of how birds use garden berries and answer key questions to deliver better advice for people to plant the most fruitful berry producing plants for our garden bird visitors. My rowan tree had already been stripped bare by blackbirds by late August. I would like to take this study back a stage, to the pre berry stage, i.e. the flower!

Bumblebee pollinating a blackberry flower

 Hedgerow aspect
The directional aspect when planting a hedgerow has the potential to exert an influence on fruit set of hedgerow plants, since insect activity can increase with light intensity, solar radiation levels and temperature. Plant physiology itself may also affect fruit setting as plant require carbohydrate, which is primarily produced by photosynthesis in the adjacent spur and leaves. Without sunlight and radiation, which would be restricted if planted in a shady area, shading has been shown to reduce the fruit yields of some orchard crops by increasing fruit abscission. Pollinator activity has been found to increase with increasing temperature, light intensity and radiation. You can see for your selves on a hot sunny day summer the activity of many flying insects/pollinators as opposed to a grey dull summers day. Obviously the insects are only busy around a certain clump of flowers if there is nectar or pollen to be gained from a visit. It simply is not worth them wasting their time if they visit and the visit is fruitless! The plant has to offer a reward, which itself is related to environmental variables such as temperature and relative humidity. Planting hedges and berry bearing plants along a south and west facing aspect, (a warm hedge), as opposed to a north or east facing aspect, (a cool hedge), could be more rewarding for pollinating insects and more rewarding as regarding fruit/berries for birds. As shade affect light levels,this affects berry production. Planting in masses and not isolated trees and shrubs separated by long distances can negatively affect pollination by bees. Quite simply, an isolated tree/shrub may just be too far, requiring a bee to expend too much energy for little reward.

Autumn. A good time to carry out shrub-butchery? Not many berries on this hedgerow for wintering birds.

 

Management or in this case, mismanagement has a huge effect on food availability for birds. These hedgerow plants may well have been pollinated by bees, but what good are they now?

Great tit with sloe in its beak

 

Our native wild bees are quietly and efficiently pollinating garden and wild flowers, fruit, vegetables, as well as the wild fruits and berries in our hedgerows and trees, providing vital food resources for birds and other wildlife, work undertaken in the main unnoticed. For example, blackthorn sloes, are fed upon by robins, blackbirds, redwings, song thrushes, fieldfares, mistle thrushes, starlings, magpies and crows. They are pollinated by bumblebees, solitary bees and honey bees. It is known that bumblebees can forage early in the morning and at cooler temperatures than honey bees. Blackthorns tend to flower early in the year. I have seen them flower in February where I live and have seen bumblebee queens forage on them. This may be too early for many honeybees, finding it too cold to forage, staying in their hives to keep warm and feed on their honey store. Whereas bumblebees will forage as they have no stores of honey and need to replenish their fat reserves after hibernation. It is likely that bumblebees may well pollinate more blackthorn flowers than honey or solitary bees.

Berries eaten by birds

Plant Pollinated by Berries eaten by
Blackthorn Bumblebees, solitary bees, honey bees, flies, butterflies, beetles Robins, blackbirds, fieldfares, redwings, mistle and song thrushes, starlings, magpies, crows and sloe gin!!
Bramble Bumblebees, solitary bees, honey bees, flies, butterflies, beetles Robins, blackbirds, song thrushes, garden warblers, blackcaps, lesser and common whitethroats, blue tits, greenfinches, bullfinches, moorhens, starlings, and us!
Dog Rose Bumblebees, solitary bees, honey bees, flies,  beetles Robins, blackbirds, song and mistle thrushes,  fieldfares, redwings, blackcaps, blue tits, greenfinches, woodpigeons
Hawthorn Bumblebees, solitary bees, honey bees, flies,  beetles Robins, blackbirds, song and mistle thrushes,  fieldfares, redwings, blackcaps, blue tits, starlings, woodpigeons, magpies, crows
Honeysucklespp. Bumblebees, solitary bees, honey bees, flies, butterflies, moths, beetles, wasps Robin, blackbird, song thrush, starling, blackcap, lesser whitethroat, bullfinch, blue tit, marsh tit
Ivy Bumblebees, honey bees, wasps*and flies Robins, blackbirds, song and mistle thrushes,  fieldfares, redwings, blackcaps, greenfinches, starlings, woodpigeons

Red wing eating hawthorn berry

 

Without bees, very few berries would be produced for birds and mammals.

Although some of the above species are true berry eaters, such as blackbirds, which digest the fruit pulp and disperse the seeds, others such as greenfinches are ‘seed predators’. I have seen them rip open dog rose hips, discarding the pulp to purely get at and eat the numerous seeds inside, thereby not distributing the seeds.

*Wasps, in terms of what use are they, (a question I am forever asked!), besides being efficient predators of many garden pests, recent research has found that wasps are extremely beneficial as pollinators of ivy, the berries of which provide food for birds, e.g. blackcaps, which use ivy berries as an important food resource.

For those of you that like sloe gin, thank this cuckoo bumblebee!

 

You highly likely will have different species of wild bees already visiting your garden, busy pollinating your fruit, flowers, vegetables and yes wild flowers that help to make our gardens and countryside a beautiful place. If you feel that honey bee keeping is simply not for you, then consider looking after the wild bees and other pollinators that, themselves are also declining, by planting appropriate flowers and offering bumblebees and solitary bees a home, allowing you to observe the hidden world of wild bees.

Food preparation! More food for our birds courtesy of bumblebees!

 

Gardens as safe refuges could well help our wild bees, as they have done with many species of birds, particularly if we provide forage plants and do not use pesticides. So birdwatchers, as you avidly watch the influx of migrant birds, such as the beautiful wax wings, through your binoculars, just remember the work done by the bees earlier in the year!They have helped to provide berries for such birds as blackcaps, fieldfares,redwings and song thrushes!

Fieldfare eating hawthorn berry

 

The fruits,berries and seeds that have been pollinated by wild bees are then consumed by birds that then facilitate the dispersal of seeds away from the parent plants with the potential to germinate and create a new population of those plants to be pollinated by the bees for the birds!

Read more articles about bumblebees.

For more information about my award winning bumblebee and solitary bee boxes.

For more information and to help save bumblebees join the Bumblebee Conservation Trust at Stirling University.

For more information about the BTO Garden Birdwatch scheme 
Refs. Besides my own observations and experiences:
Jacobs, J.H ( 2008) ” The birds and the bees: pollination of fruit-bearing hedgerow plants and consequences for birds” PhD thesis University of Stirling.
Potts, S.G., et al,  (2010) Global pollinator declines: trends, impacts and drivers. Trends in Ecology & Evolution, 25, 345-353.
Snow B and Snow D, (1988)” Birds and Berries”, T & A D Poyser Ltd, Waterhouses, Staffs, UK.
Thanks to Roy & Marie for the bird photographs…..

 

 

 

 

 

 

 

 

 

 

 

{ 2 comments… read them below or add one }

Amanda December 4, 2012 at 6:38 pm

This is lovely George. People often don’t think about bedgerows and trees for bees (I have a page about this on my site). Yet of course, hedgerows benefit so many species. Indeed, abandoned rodent holes at the bottom of hedgerows make popular nest sites for bumblebees too. I quite agree with you regarding wasps, by the way. Although they tend not to be popular, they are very good pollinators of many plants – including raspberries, for example. I have seen it written that wasps do not pollinate because they lack hair – this is untrue, and anyone finding a dusty, deceased wasp on a window ledge will realise they have a good amount of transparent hair, now made visible by the dust!
Again, thanks for this lovely piece.

Reply

George December 5, 2012 at 8:47 pm

Hi Amanda, Thanks. It would appear that wasps, when on ivy have to, because of their short tongues, forage lower down into the ivy flower than bees. They therefore make frequent contact with the stigma with its pollen bearing heads! Best wishes from, George

Reply

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