Don't crop it. The composition is just nice, but sadly the quite bright grass behind the bird has fooled the light meter and the bird is extremely underexposed. You can compensate with shadows/highlights or if you have RAW try to superimpose same picture with different exposure compensations (once underexposed, other time overexposed) to get the bird details out.
But don't blame yourself, under such conditions it's always almost impossible to correctly expose the shot. Either the bird is underexposed or the background is overexposed.