There were two more postings to the bird group on February 14 under the title

"More on those Migrating Butterflies"

"Incidentally we went through the largest butterfly migration I have
ever seen on the way back from Moshi. Millions of whites all heading
south from Moshi all the way to Karatu (Karatu is in the Crater Highlands along the western edge of the Rift Valley). In places it resembled a blizzard. We've collected a few off the radiator.
Grant Hopcraft - Frankfurt Zoological Society"

"Those Brown-veined White butterflies that were mentioned the other day. They passed through Naivasha and the Rift last week, laying thousands of eggs everywhere. Their favoured food plant is a three-leaved indigenous bush that becomes devoured by the caterpillars before they move into the grass.
Am sure your local agricultural officers are well aware of it all and are spraying (sic!).
Don Turner, Naivasha, Kenya"

On 15 February I wrote to friends:

"The area and duration of this Belenois movement in Tanzania and Kenya would seem to be extraordinary.

I first became aware of the B-v White et al. migration on Tuesday afternoon February 6 as I drove with Jack & Kathy Wigan towards Chalinze from the Saadani junction.

Returning from Dar to Arusha the next day (7/2/07) they were an almost constant feature as they crossed the main road more or less southwards during almost the entire journey.

Vast numbers were also present on the Angyata Osugat on February 13 nectaring on the flowering Acacia mellifera.

Huge numbers, frequently reminding me of highland snow storms in mid-May (Scotland), have been passing through Kwaiidi in western Arusha (and also southwards at Maweni farm (at 1000m) and thus they are therefore easily crossing the West Usambara barrier too) all this week, especially on Wednesday 14 and today Thursday 15 in Arusha."

My (butterfly-watching) hero Torben Larsen says in the Butterflies of Saudi Arabia:

"Some migrants are able to build up spectacular populations in a very short time, far surpassing the density of sedentary species. In addition, they may avoid their normal predators, whose numbers cannot increase fast enough to take advantage of the temporary surfeit of potential prey. There was hardly any mortality due to parasites or disease among the more than 500,000 Caper Whites (Anaphaeis [= Belenois] aurota) which hatched in May 1981 in a wadi in Oman."

Geoff Harries' detailed observation from a light aircraft at high altitude is fascinating.

"On a flight from Kilimanjaro to Nairobi on 18th February, at about 11.30 am, climbing through around 8500ft in a Cessna Caravan just north of West Kili airstrip (nearly over Sanya Juu - at co-ordinates S03.03.00 E 37.00.00 and 4000 ft altitude) I passed through quite a dense mass of butterflies (I assume Belenois aurota), for about 15 seconds or so, streaming past both sides of the aircraft.

Earlier on take off at Kilimanjaro airport, (this is 3000ft asl) , there were thousands of these butterflies crossing the East-West runway in a southerly direction only a few metres off ground, enough to actually keep the inertial separator out, to prevent them being ingested by the engine.

After that none that were noticeable until passing the higher altitude.

Over the period that they have been around, I noticed many more of them at KIA compared to Arusha airport and actually at one stage I did compare it to a snowstorm!"

David Fisher reports on February 21:

"I saw millions - yes, really millions - of Caper/Brown-veined Whites in Tsavo East and West two weeks ago. It was the most amazing butterfly migration I have ever seen."

And finally a note from Torben Larsen and a request for more information:

"Well that sounds like something on the scale of the migration that I once saw in Botswana.

I really think it would be good to try and get as much data as possible on this. I made a little checklist for Grant Hopcraft, which I have converted to an appeal for assistance. I am copying this to some lepidopterists in the area.

If various organizations in Tanzanai could circulate this and collate the replies that would be great. But I think the most important thing is to get maximum evidence from observers while it is fresh.

I am particularly interested in Geoff's observations.

In the Botswana paper I mention that the migration at one point was so intense that a bush pilot had to abandon landing a Cessna 172. Also of interest to him is that in 1975, when I was following a huge migration in the Kenyan rift, I went up to check at 9000ft in the Aberdares. The migration was fine whilst there was sunshine. When a cloud passed over it became cold and butterflies started raining down!"