Seagulls on roof

Dear Evil Engineer: Could I fire-bomb my office with a flock of incendiary seagulls?

Image credit: Dreamstime

This month’s correspondent is determined not to return to the office, even if that necessitates using hundreds of gulls to burn it to the ground.

Dear Evil Engineer,

If I were in senior management, I’d insist office-based working is essential for employee productivity and company culture. However, I am not, and I refuse to tolerate the proposed return to the office after 18 comfortable months of working from home. I hate the anonymous openplan office; I hate the commute; and most of all I hate the mob of aggressive gulls that descends on anyone walking back to the building at lunch with a meal deal.

I plan to kill two birds with one stone; the two birds being the return to the office and the gull mob, and the stone being an incendiary seagull bomb. Is it possible to weaponise the flock of gulls to take out the office building?

An ornithophobic villain


Dear villain,

Gulls may or may not be the villains of the bird world – they strike me as more amoral than immoral – but undoubtedly, they are gutsy, adaptable, and merciless when provoked. Urban gull populations have grown since the 1956 Clean Air Act, which drew gulls inland to feast on no-longer incinerated landfill waste. Now there are massive and ever-growing populations of gulls that enjoy nesting comfortably in roofs and scavenging/stealing human food.

Humans have experimented with using birds as incendiary weapons since our ancestors found smacking other people with rocks and sticks was a good way of getting what they wanted. Pigeons, sparrows, and cockerels have all been used or contemplated for use as wartime flamebearers. The most ambitious incendiary animal-based weapon, however, was the Bat Bomb: an experimental US weapon developed during the Second World War. It was suggested by Lytle S Adams, who argued that bats were completely crap and the only feasible explanation for their creation was that God meant for them to be weaponised. The Bat Bomb contained over one thousand compartments, each housing a hibernating bat wearing a timed incendiary device. The idea was that once released, the bats would disperse and roost in eaves and attics, igniting the wood-and-paper buildings common in Japanese cities at the time.

Each bat had a 15-18g payload of napalm in a cellulose container glued to their front. They proved remarkably effective during two large tests (one planned, one unplanned) and the concept was only binned because the Manhattan Project was proceeding so quickly in comparison.

Let us presume, then, that you plan to replicate the Bat Bomb using gulls for dispersal and your office building as the target. Napalm remains an ideal weapon for brick-and-mortar and wood-and-paper buildings alike: it clings to whatever it touches, resists suppression, and burns at more than 2,000°C. Other than the gull substitution, the only changes I’d recommend are the additions of a proximity tracking device and a homing beacon. By the former, I mean a cheap IoT set-up which triggers countdown to detonation when a gull approaches the building (similar to that which uses GPS to turn off smart home cameras when you arrive home or send a notification when you leave without your keys). By the latter, I mean a plate of chips on the roof.

Content warning for engineers: the following section contains explicit back-of-envelope working and mention of imperial units.

Let us first consider how much damage must be done. You have not told me how large your office block is, so I’ll pick some numbers and you may scale afterwards to suit your circumstances. An often-cited allocation of 100 sq-ft of space per employee gives you, for a 200-person office building, 20,000 sq-ft of office space (in grown-up units, 1,860m2). The typical land-to-building ratio in the UK is 3:1, and three floors for 200 employees sounds sensible, so let’s call it 620m2. A firebomb containing 750L of napalm can devastate an area of 2,100m2, giving us a square-metres-damaged-to-litres-of-napalm ratio of 2.8. Comparable damage to this hypothetical office building will take 221L of napalm. Using the US Army’s modern Mark 77 incendiary weapon for reference (284L; 250kg), we find that a napalm weapon has an approximate density of 0.88kg/L; therefore you’ll need 195kg of napalm to raze your office.

Now: how many seagulls must be sacrificed to carry this napalm? Non-raptor birds can carry up to half their body weight. British gulls weigh anything from 0.5-1.1kg, so have a payload of around 400g. Accounting for 100g each for a small computer and GPS tracker, that leaves around 300g of weaponised payload per gull. So, devastating your office building would take 650 birds.

In reality, this is a conservative estimate – even accounting for a fraction of the incendiary birds not detonating – as military-scale destruction isn’t essential for securing a few extra months working from home. The proposed Bat Bomb was a magnitude smaller in terms of
napalm volume!

In fact, I suspect that one of the hardest tasks involved will be catching the birds themselves; they’re not stupid, and if a few of their number are entrapped, others may know to avoid you. Therefore, I suspect your main limitation is how many gulls you can be bothered to catch. I’m comfortable saying that anything from around 65 birds could cause a good deal of damage.

Now, most of the figures in this calculation condense down to a constant, leaving us with a formula which gives a conservative estimate for how many gulls you’ll need to flatten an office building. Here is it: Number of birds = 23 x number of employees x bird payload (kg) / number of floors.

The Evil Engineer

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