The research seems credible, and they've convincingly excluded obvious things like that they're actually aligning with the sun.
The striking thing is that they only align N-S when the declination of the magnetic field is stable, but when the declination is changing they don't align. The differences in magnetic field direction is only a few degrees, so it's amazing that a dog whose head is flopping around can detect such small changes.
>they've convincingly excluded obvious things like that they're actually aligning with the sun.
I don't know - for my taste, to exclude alignment to the sun they would have had to keep the dogs in a closed environment with an artificial light source. After all, even with clouds present you know where the sun is (and you can still get sunburned etc.)
It also rings my "skeptical" alarm bells when they cite the "original" evidence that cattle aligns along the N-S axis, but they don't cite the paper that fails to replicate the "original" findings in cattle: http://link.springer.com/article/10.1007%2Fs00359-011-0628-7
The striking thing is that they only align N-S when the declination of the magnetic field is stable, but when the declination is changing they don't align. The differences in magnetic field direction is only a few degrees, so it's amazing that a dog whose head is flopping around can detect such small changes.