“Honey bees do not mind being quite high up”: but is rooftop bee-keeping a good idea?

Bee hives atop Fortnum & Masons. Image: Getty.

What links the London Stock Exchange, posh grocer Fortnum & Mason and the Scottish parliament building in Edinburgh? All great institutions, of course, but they have also proudly introduced beehives to their rooftops. The Conversation

In the midst of worrying stories about declining bee populations, it has become a popular pursuit. Businesses and government install the hives with great fanfare to signal their green credentials. But is this actually a good thing for honey bees, beekeepers and the public?

For beekeepers it is clearly more convenient to keep hives at ground level. The bees do fine, and level locations are plentiful in most areas. Both ground and roof locations require beekeepers to carry out routine and seasonal management, such as hive inspections and honey harvesting. However, hive equipment is bulky and heavy. Steve Benbow, a commercial beekeeper in London, has described the effort of carrying hives to the roof of the Tate Modern art gallery via chambers, lifts, corridors, and a final ascent up four flights of stairs. Moving stuff is a lot easier at ground level.

High honey. Image: author provided.

Swarm behaviour

Then there are the swarms. Each spring, beekeepers have to manage this natural part of the life cycle in which a colony divides – swarming is how honey bee colonies reproduce. The swarm, when it leaves the colony, can contain 10,000 bees. Beekeepers manage their hives to prevent swarming. However, prevention is never 100 per cent. If swarming does occur, the swarm usually settles near the parent hive and can then be put into an empty hive and moved to a more convenient location.

Swarming from a rooftop probably makes little difference from a bees’ perspective. But the swarm is liable to be more of a public nuisance. Mark Patterson of the London Beekeepers Association told us that swarms from high-rise hives often settle high. He recounted episodes of abseiling down buildings, calling in the fire brigade and using window-washing platforms to collect central London swarms originating from high-rise hives.

Swarm! Image: Grande Illusion/Flickr/creative commons.

So much for our convenience, what about the bees? Well it is true that honey bees actually prefer to nest above ground level. Tom Seeley, a honey bee biologist at Cornell University, has shown that swarms are picky when selecting a nest site. By attaching plywood bait hives to trees he found that swarms prefer five metres above ground to one metre.

When Seeley located wild honey bee colonies in hollow trees in a nearby forest he found the average height was 9.7 metres (in a range of between 5.3 and 17.3 metres). That’s about three storeys high.

This shows that honey bees do not mind being quite high up, at least when nesting in a forest. We don’t actually know why honey bees in the wild prefer not to nest at ground level. It may provide protection against predators such as bears. Urban hives at ground level are unlikely to be predated, other than by humans, of course.


Altitude attitudes

In the UK, hives on iconic buildings such as St Paul’s Cathedral in London, can be very high up, 52 metres in that case. This is higher than bee colonies live in trees. Is this good for the bees? As far as the risks to a successful colony go, James Fischer, a New York rooftop beekeeper, told us that hives above 10 storeys are “speculative ventures”; those above 15 stories are on “life support”.

Research has yet to establish if height itself is an issue for honey bee colonies. Honey bees routinely forage several kilometres from their hive. To a bee, flying level or flying vertically should make little difference as air resistance, not gravity, is the main challenge. Flying vertically to a hive at 50 metres would be negligible extra distance.

More obvious is the fact that apiary sites should not be too exposed. Beekeepers know that good locations should be sheltered from the wind and this may be harder to achieve on roofs. Tall buildings often cause the wind to form unusual draughts and eddies.

Sweet reward

What is the real motivation for keeping rooftop hives? With trendy London honey retailing at up to four times the price of a similar Leicestershire honey, financial reward is one incentive. A somewhat different motivation is the desire of businesses and government bodies to showcase environmental credentials, by helping to save the “endangered” honey bee.

Image: National Bee Unit, Author provided.

However, this may not actually be helpful, particularly when it adds more hives into an area where there are already many, as seems to be the case in London. More hives increase the risk of spreading bee diseases and annoying neighbours. Overstocking can also increase competition for nectar and pollen which is not good for honey bees or beekeepers, or other pollinator species. Many towns, and especially central London, probably already have as many hives as the available flowers can support. Most people will have no clue that each new hive will consume the floral resources produced by the equivalent of eight hectares of lavender.

Keeping bees can be a fascinating hobby. And with the surge of interest in urban farming, sustainability, food security, and the environment – as well as intense media focus on bees – it is not surprising that beekeeping is becoming increasingly popular. People who take up beekeeping or staff who join corporate beekeeping projects often report genuine benefits such as more contact time with nature.

But beekeeping isn’t easy. For a novice, the reality can easily be dead colonies and no honey, rather than the hoped for abundant harvest. Once people start to question the motivation for installing yet another rooftop hive, they may find that more benefit could be gained, for bees, humans and other flower visiting insects, by growing flowers that provide nectar and pollen for all pollinators.

Karin Alton is a research fellow in, and Francis L. W. Ratnieks professor of, apiculture at the University of Sussex.

This article was originally published on The Conversation. Read the original article.

 
 
 
 

The Delhi Metro: How do you build a transport system for 26m people?

Indraprastha station in 2006. Image: Getty.

“Thou hath not played rugby until thou hath tried to get onto a Delhi Metro in rush hour,” a wise Yogi once said.

If you’ve never been on New Delhi’s Metro, your mind might conjure up the the conventional image of Indian trains: tawdry carriages, buckets of sweat, people hanging out of windows and the odd holy cow wandering around for good measure.

Well, no. The Delhi Metro is actually one of the most marvellously sophisticated, affordable, timely, and practical public transportation systems out there. On a 45C day in the Indian summer, many a traveller has shed tears of joy on entering the spacious, air-conditioned carriages.

Above ground, Delhi is a sprawling metropolis of the scariest kind: 26m people, three times the population of London, churn and grind through Delhi itself.

The National Capital Region, an area which includes Delhi and its surrounding satellite cities – now victim of its never-ending urban sprawl – has an estimated population of almost 50m. So how do you tie such a huge population together?

The map; click to expand. Image: Delhi Metro Rail.

Motorised vehicles won’t do it alone. For one, air pollution is a horrific problem in Delhi, as it is across India. Last November, the government declared a state of emergency when the Indian capital was engulfed by a toxic, choking fog so thick that you could barely see several metres in front of you, drawing allusions to the great Victorian fogs in London.

Then there’s Delhi’s famous traffic. Twenty-five years ago, the travel writer William Dalrymple observed that you could reduce the Delhi’s road laws to one simple idea: the largest vehicle always had the right of way. The traffic has tamed somewhat in the 21st century, but the number of vehicles has multiplied again and again, and it’s not uncommon for people to be stuck in four-hour traffic jams when they try to traverse the mighty city.

Enter the Delhi Metro – a huge network of 164 over- and underground stations – and by any account, a titan of civil engineering and administration.

The numbers are simply colossal. Every day the metro serves on average almost 3m people. Annually, it carries around 1bn.

In a country where intercity trains still turn up a day late, the Delhi Metro is extraordinarily timely. On the major lines, trains will come every several minutes. The trains are extraordinary speedy, and you’ll reach your destination in a fraction of the time it would take for you to drive the distance.

The minimum fare is 10 rupees (12p); the maximum fare, to and from the airport, is 50 (60p).

The evolution of the metro. Image: Terramorphus/Wikimedia Commons.

Construction of the metro system began in 1998, with the first section completed in late 2002. Keen to avoid the catastrophic corruption and bureaucratic mismanagement which plagued eastern city of the Kolkata Metro, developers took advice from Hong Kong’s high-tech system There have been several stages of development to add extra lines; more is planned. By 2020, it is hoped that the 135 miles of line will have increased to over 300.  

One thing quite striking about the metro is its women’s only carriages at the rear and the front of the train, marked by pink signs. Sexual assault and harassment has been a horrific problem on Delhi’s transport systems. Women can of course go anywhere on the train – but men who violate the carriage system will have to deal with the scathing anger of the entire pink carriage.


One of the under-discussed impacts of widespread and well-used public transportation systems is their propensity to break down social and class barriers over time. As the London Tube began to be used more and more in early 20th century London, people from completely different walks of life and classes began to brush shoulders and share the same air.

The story is similar in Delhi. The necessity of the metro helps to break down old caste and class divisions. Of course, many elite Delhiites would not be seen dead on the metro, and choose their private chauffeur over brushing shoulders with the common man. But slowly and surely, the times are a changing.

What’s more, the Delhi Metro system is one of the greenest around. Six years ago, the Metro was the first railway system in the world to be awarded carbon credits from the United Nations for helping to reduce pollution in the capital by an estimated 640,000 tonnes every year.  

All praises sung and said, however, at peak times it’s less mind the gap and more mind your ribs – as a fifth of humanity seems to try to get on and off the train at once.

Want more of this stuff? Follow CityMetric on Twitter or Facebook