Is a 300mm lens good enough for bird photography when isntalled on a camera with a 1.6x Crop sensor?

I have read that the generally accepted rule for bird photography is that you need at least a 400mm lens in order to cover enough distance from your birds. But this generalized rule applies (I am guessing???) to cameras with a Full Frame sensor.

What about a 300mm lens, installed on a camera with an APS-C sensor that has a crop factor of 1.6x?
The 1.6x crop factor turns your 300mm lens into a 480mm Full Frame equivalent. And 480mm is more than the accepted minimum of 400mm.
So the 300mm lens should be more than good enough when used with a crop sensor camera.
Or am I getting this whole deal wrong?

I do realize that the APS-C will be slower, darker and noisier, and that it will have a deeper depth of field, but that's not what I am interested in.
So my question is: in terms of pure zoom capabilities and magnification, is a 300mm lens good enough for photographing small birds from a considerable distance when installed on a camera with an APS-C sensor?
Anyone here tried this before?

Thanks!

Only if you are close. I used to use a 7D II with a 300 f4 around the yard sometime but most of the time it had the 600 on it.

I agree with Bill. In general you can take good wildlife/bird pictures with 500mm. But for small birds and a considerable distance you need more mm. I use 700mm(on FF) in my garden and even at 3-4 meters distance it's not enough to fill the frame with a small bird(like tits/wren etc.).

Thanks, guys. Great advice.
I didn't know that even 700mm on a FF is not enough for photographing small birds. Note taken!
It looks like I need at least a 500mm lens for my crop sensor, in order to get a 800mm Full Frame equivalent.
I guess more is better, so I will skip on the 300mm offer and may get myself a Sigma that goes up to 600mm (which will give me 960mm FF equivalent).

Canon EOS 100D wrote in post #19552289
Thanks, guys. Great advice.
I didn't know that even 700mm on a FF is not enough for photographing small birds. Note taken!
It looks like I need at least a 500mm lens for my crop sensor, in order to get a 800mm Full Frame equivalent.
I guess more is better, so I will skip on the 300mm offer and may get myself a Sigma that goes up to 600mm (which will give me 960mm FF equivalent).

Don't get me wrong, it's enough if you can get close enough and using a camera with high MP there's room to crop. And maybe you don't always have to fill the frame with the bird, environment can be good.
I van only dream about 800-1200 mm lenses (with large aperture) but realistically if those are needed I'm often more limited by atmosferic disturbances/heat shimmer. Like this western marsh harrier, would love to be a lot closer(already cropped to 2300px long side from 8000, this is not the quality I aim for or would normally show) but look at that air:

I've used the 300 f/4L on my old 7D both with and without the 1.4 tele-convertor.
I still use it with my 5Diii.

If you're reasonably close to the birds then it's OK.
I've not had much of a problem when at some RSPB reserves.
But... there will always be times you might need something longer.
But, for me the 300 f4L + 1.4x is a reasonable compromise of size, weight, and image quality, to carry around.
Also... I do rather like the images it produces.

You could get yourself a cheap 70-300 zoom from eBay et.al. to try and see.

Thanks. I may get a 300mm just to get my feet wet and at a low cost

I use a 7D with the 100-400 and my 1.4 is almost always mounted on it. No matter how much lens you have, you'll want more when doing birds. Obviously which bird and where matters but as much length as you can get is desirable. If I were going bargain hunting to start I would get the version 1 of the 100-400 and pick up a 1.4. ..

Canon EOS 100D wrote in post #19552372
Thanks. I may get a 300mm just to get my feet wet and at a low cost

If you're on a budget (and who isn't?) let me steer you to a Canon 400 5.6L. It's sharp as a tack, relatively small, very much hand holdable, and you can find used ones for $500-600.

I've used that lens across 4 different crop bodies and the 640mm of effective focal length makes for a very decent reach kit. Take a look at my gallery here. I've got dozens, maybe hundreds, of bird photos made with that lens.

It's a great lens, very sharp and excellent for close-up work as well. But I did find the AF a bit slow. Had one for a couple of years and used it on a full-frame.

drsilvers suggestion of a 400 is also an excellent idea. Great lens.

My .02c

It also somewhat depends on the AF capabilities of the camera body. They vary. But you should be able to get excellent photos with that combo if you re reasonably close to the subjects. This of course depends on situation and where you live (I bring this up because in most parts of the US the birds are really far away. Here in Florida there are more opportunities to be closer to the birds in many situations. Good for starting out!! You will wish you had more lens at some point, though.

That being said if you have an EF system then the suggestion to get the old standby 400mm f5.6 is a most excellent one. It is still a great lens, light and easy to use. Just have to work around lack of stabilization. I had one for years and it was a very nice lens.

I have no idea how it would work on an RF body. Probably great.

The Sigma should also work well (I had a Tamron 150-600 on a 7DII for years with good results) on a crop body if you have enough light. It's heavy though!

This depends on your ability to approach your subjects. Generally, I view the 300mm as okay for birds in some smaller yards, but a bit too weak for serious field work - unless you can sneak up on the birds or draw them to a blind.