I sought further information from our Cuban friend Félix, a butterfly enthusiast in Gibara a few miles to the west, and his reply the same day was very interesting. He confirmed that a huge migration had been taking place. He said that migrations occur most years between May and July often lasting between three and five days followed by a gap. The most abundant species are Great Southern White Ascia monuste and Lyside Sulphur Kricogonia lyside, with Cloudless Sulphur Phoebis sennae, Large Orange Sulphur Phoebis agarithe and Cuban Snout Libytheana motya present in smaller numbers.
This year he says that in April there was a large migration of Great Southern White Ascia monuste with a few Lyside Sulphur Kricogonia lyside - unusual so early in the year. During the last twelve days of May there was a huge migration of mainly Great Southern White Ascia monuste from the NE which has also been seen in Holguin, Banes, Guardalavaca and Puerto Padre mainly between 8am and 1pm. This migration also included some Cloudless Sulphur Phoebis sennae, Large Orange Sulphur Phoebis agarithe and Lyside Sulphur Kricogonia lyside but these were scarcer.
Thank you Félix for your insight and to Ronald for first alerting us to this – just a shame we aren’t there to witness it for ourselves.
Postscript - I have since heard from Douglas Fernández who lives at Camagüey in the centre of the island who tells me that on 25 May in his neighborhood he and his wife Norris watched many Great Southern White Ascia monuste flying north after midday at a rate of about 100 per minute. And again on 27 May he and his son Douglas saw many flying north over the savanna grasslands at Albaiza, a few km outside Camagüey. Thank you Doug for sharing.