How consistent are trends in arrival (and departure) dates of migrant birds in the UK?

How consistent are trends in arrival (and departure) dates of migrant birds in the UK?

Journal of Ornithology, 2007

Citation

Sparks, T.H., Huber, K., Bland, R.L., Crick, H.Q.P., Croxton, P.J., Flood, J., Loxton, R.G., Mason, C.F., Newnham, J.A. & Tryjanowski, P. 2007. How consistent are trends in arrival (and departure) dates of migrant birds in the UK?. Journal of Ornithology 148: 511. doi:10.1007/s10336-007-0193-6