Bird understands how motion sensors work

Originally published at:


I always feel very badly for this bird’s less wise relatives, who i keep seeing flying desperatly around the insides of high ceilinged big box stores, hopelessly confused because their instincts tell them to escape stress by going up, but the only exits to the outside are way down low near the ground and the scary humans.


I would like to be the first to welcome our benevolent Bird Overlords.


Mama bird didn’t raise no fools.

Edit: this video seemed familiar and after a bit of searching i now recall why. Can’t don’t remember if this was posted here in BB or elsewhere


That bird is now officially more qualified to be president than Mango Mussolini… Good bird!


I have a friend who did pest control - specifically exclusion of nesting birds - in a variety of big box stores, grain elevators, etc., etc.

He told me that small birds - sparrows, finches, certainly starlings - get very smart, very quickly when pressured. They began to recognize his truck and his uniform and if he didn’t remove the pest birds on his first trip it became very, very difficult to remove them on subsequent site visits.


I, for one, welcome our new avian overlords.



The store may think they’re pests, but I think it’s more accurate to say they’re victims – they’ve accidentally gotten into a place with no bird food, no water, and no navigational cues they understand. All they want is to get back to their family before their children get hungry, and instead all these people are constantly blocking the doorways, assuming they can even figure out where they doorways are, and chasing after them with nets and such.


Do door openers work by ultra-sound? I wonder if it’s possible that the birds can hear the sensors?

Google thinks that motion detectors in automatic doors usually work by detecting motion optically. Exactly how that works, nobody in the top hits bothers to explain, but I know I’ve been encountering door openers that you could activate by waving your hand in the direction of the sensor since before the Internet, so it must be based on something simple and non-computational.

Blasted misinformation on the internet strikes again. Motion detectors work by radar or sonar principles: using infrared, microwave, or ultrasound, they notice when the signals they send out come back faster than usual, interpret that as someting in the doorway, and open. So, yes, some doors use sound and the birds might hear it, but considering all the noises in a store that they have no idea what they mean, it seems a lot more likely they have learned by observing humans use the doors.

BTW: The birds I have seen getting confused inside big box stores have invariably been wandering around up near the high ceilings far above where the doors are, and these door-using birds in the video are in a store with much more normal height ceilings. A big box store breaks all the rules that birds understand about enclosed spaces like caves or dense thickets (the brightest light is nowhere near the exit), and birds respond to big noisy scary animals (like us) by flying up. Combine no windows and artificial lights with high ceilings and you can get a very confused little birdie.


Poor guy forgot his take-out order.

1 Like

Some places have food and shelter that attracts these birds, and the birds have a long history of hanging out where humans are because of the food and shelter: Many big box stores sell bird food, which draws house sparrows especially, so they live and nest there, or try to. I’ve seen house sparrows in train stations with automatic doors, because the place had a food court. These birds have lived around humans for a long time because of the various food opportunities, originally because of the farming that produced food they like (the crops and the bugs that fed on the crops), and the shelter. They’re called house sparrows because they’ve always liked to nest in human dwellings, btw.

But as house sparrows and starlings are not native to the Americas, these birds can be killed as pests and their nests destroyed. (Per the Migratory Bird Act, most native species are protected from harm, and their nests can’t be messed with while in use.)

1 Like

The ones in my local big box stores build nests and raise their families inside. There’s plenty of food available to them in the Home Despot and sLowes!

I always feel sad when I see the bodies of the ones that ate the treated grass seed or whatever, though.

Admittedly I have not taken time to observe them closely because when I am in a big box store my first objective is to get what I came for and get the hell out. But the ones I have seen always struck me as acting “little bird lost” rather than “little bird in comfy rainproof, cat-free home.” Maybe I am unobservant.

However, what the fuck would they eat in a home depot? I can sort of see them scrounging from the produce in a supermarket or wal-mart. But a home depot?

I imagine it saying “I’M TINY BIRD RIIICK!”

1 Like

Hospitals in the Australian tropics have serious problems with malarial mosquitos.

At night, the mozzie swarm in front of the lights over the door is often dense enough to trigger a door-opening sensor.

So, they build the clinics with multiple layers of doors, to function as a pseudo airlock. I think some may also use a bit of elevated air pressure within the building to push them out.


Elevated air pressure within those airlock style entryways is fairly standard. The idea being to keep the outside air outside. You see that style of entry a lot in areas of the US that get a lot of cold weather and snow for instance.

Seeds, insects, and plentiful human food waste. Sadly also some toxic things. Check out the beak-holes in the grass seed bags.

Word, father of dragons, testify!

1 Like

I watched some birds fly around in a Home Depot once. They were just playing tag and chasing each other around endlessly. There was no eating or fighting, no seeking of exits. They were just goofing off. So much free time, spent wisely IMO.

1 Like