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How far birds are from each other in a migration flock? (1 Viewer)

Benberi

New member
Hello,

First of all I will introduce myself,

I work with a weather radar in order to find flocks of birds and track them.
It doesn't really matter why I do this but it's really important for me to track their movement and see where they direct to.

So a big problem I have currently is noises. I have a lot of clutter noises from the radar and basically what happens is that the program that I wrote thinks that a noise is a bird.

The parameters that I check are:

DBT/DBZ is the size of the flock
V is the velocity of the flock as in speed generated by the radar
V2 is the velocity that I calculate myself by position change in given time
W is how spread the target is
SQI - forgot my mate used it
height - The height of the target
heading - The angle of the target

So what I am doing is, whenever I receive the data from my radar, I group all targets I find into flocks, and then I start going through the next data files and see if i can see any of the flocks i found in the previous data file that are very similar so I can mark them as one flock that just moved.

But the thing is, my program loves to mark noises as flock movement.
And to avoid that, I need to tell the program how to compare between a noise and a bird target.

And this is almost impossible because the nosies are really similar in data parameters as a bird should have.

So lets go back to the title question:

In reality, we are mostly talking about flocks of Cranes, when they fly together, usually, how far are they from each other inside of the flock and what shapes do they usually create when flying together? and do they often change their shape on flight? Do they often make changes in their height during the flight?

If I know the approx distance between each crane or any other bird type, I can add this option to the filter to limit the distance between targets in a flock to avoid acceptance of noises.

If you have any other ideas on how to compare between a noise and a real flock, please let me know! Basically the idea is implementing kind of an artificial intelligence of a bird to the program so it knows to detect that the found flock really acts like one, as in the movement inside of the flock.

Thank you! o:D
 
Last edited:
Hello,

First of all I will introduce myself,

I work with a weather radar in order to find flocks of birds and track them.
It doesn't really matter why I do this but it's really important for me to track their movement and see where they direct to.

So a big problem I have currently is noises. I have a lot of clutter noises from the radar and basically what happens is that the program that I wrote thinks that a noise is a bird.

The parameters that I check are:

DBT/DBZ is the size of the flock
V is the velocity of the flock as in speed generated by the radar
V2 is the velocity that I calculate myself by position change in given time
W is how spread the target is
SQI - forgot my mate used it
height - The height of the target
heading - The angle of the target

So what I am doing is, whenever I receive the data from my radar, I group all targets I find into flocks, and then I start going through the next data files and see if i can see any of the flocks i found in the previous data file that are very similar so I can mark them as one flock that just moved.

But the thing is, my program loves to mark noises as flock movement.
And to avoid that, I need to tell the program how to compare between a noise and a bird target.

And this is almost impossible because the nosies are really similar in data parameters as a bird should have.

So lets go back to the title question:

In reality, we are mostly talking about flocks of Cranes, when they fly together, usually, how far are they from each other inside of the flock and what shapes do they usually create when flying together? and do they often change their shape on flight?

If I know the approx distance between each crane or any other bird type, I can add this option to the filter to limit the distance between targets in a flock to avoid acceptance of noises.

If you have any other ideas on how to compare between a noise and a real flock, please let me know! Basically the idea is implementing kind of an artificial intelligence of a bird to the program so it knows to detect that the found flock really acts like one, as in the movement inside of the flock.

Thank you! o:D

Cranes and similar large birds tend to fly in a string, at the same altitude and with each bird maybe a couple of wing lengths away from and behind the leader. So there should be a periodicity in the signal when they are in formation.
That said, they also sometimes bunch up, especially if they are considering a pause for some reason. In those cases, they can be much more randomly spaced.
The spacing for smaller birds is a lot more random, not even the altitude is the same for the flock participants.
David LaPuma, the director of the Cape May Bird Observatory, used to publish US migration radar updates earlier in his career. He might be able to help add more useful insight. His email is: [email protected] .
 
If you google "Migrating Common Crane" you should find many images of flocks in flight. You may be able to calculate the distance between birds by comparing the gaps to the wingspan of the birds:- 180-240cm (according to Wikipedia).

They often fly in V formation which can remain stable for considerable distances but as Etudiant says they have a habit of bunching up on occasions. Really big flocks can be a lot more fluid, breaking into smaller strings and then reforming, but presumably they're easier to pick up on radar? Watching them on their annual migration (both ways) in France flocks are usually at similar altitudes, only a few hundred metres above the ground (at least where I live). I believe they fly mostly by visual clues so don't go way up like migrating raptors often do. Maybe this is not the case if they're about to cross some kind of barrier (like mountains or water)?

There are birds with satellite transmitters being studied (which may have altitude recorders) there are also birds which have been tracked by microlights, so somewhere there should be pretty specific altitude data.
 
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