cover crop planning

the cover crops that I planted were meant to have sun,
it has been about a week from when the snow fell, and here is what the plots look like today

I found bird foot prints in the snow...

snow just does not usually last this long here, it is melting now, and it is gone from the sunny locations,
and it is likely to hurt the tiny seeds that were just sprouting when it snowed,
so I better come up with an alternate method of adding organic matter and nitrogen to the soil before spring,

right now I am thinking that if the cover crops fail, then I will just go get oak leaves and add them like I did last year, it is reliable, but is lots of work