Here's a link to a simple side-by-side comparison of the specs:
https://www.imaging-resource.com/cameras/nikon/p1000/vs/nikon/p950/specifications
As you will see, the P1000 has a bigger zoom: 24-3,000mm equivalent, compared with the P950's 24-2,000mm.
The P950 is lighter than the P1000 but quite a bit more expensive.
As to which is better for bird photography, they will both do a good job. It depends on how much the extra reach matters to you and if you're prepared to carry the extra weight in order to have it.
Malcolm