Of special concern is the recently described and endangered endemic Henderson petrel Pterodroma atrata. But all the ground-breeding petrels on Henderson are hugely threatened by rats. Evidence from fieldwork has shown that rats kill 95% of petrel chicks on Henderson within the first week of hatching - over 25,000 chicks every year. An appeal to raise £1.7 million, spearheaded by the RSPB, plus some UK Government funds has enabled a rat eradication programme on Henderson.