Tuesday 28 April 2020

Migrating Monarchs

Being self isolated has added to my knowledge of natural history - little did I realise how few species populate the garden and how slowly the populations change, or how many specimens fly in then immediately depart. Photographic opportunities are fleeting.

The  isolation has at least one upside, I can now catch up on processing a large backlog of photographs. Not least my trip to Cape May in New Jersey back in late September, which was primarily to witness the Eastern Flyway, but afforded me the opportunity to witness another key migration, that of the Monarch Butterfly, Danaus plexippus.

There are few true migrating butterflies, the two that immediately come to mind are Painted Ladies and the Monarch. Both occur in spectacular numbers and travel huge distances. In the Monarch's case millions migrate each year, all heading to one location - the forest mountains of central Mexico. A journey entailing distances of over 2000 miles. Of course the attrition rate is high, unable to tolerate prolonged freezes, many perish. However, the cool mountain temperatures in Mexico allow the butterfly to spend the North American winter in hibernation. In early spring rising temperatures break their sleep and they start the northerly migration, As the Milkweeds of Northern Mexico and the southern United states appear, the larval host plant, the females lay their eggs. It is the progeny of this first wave that will repopulate North America. Two or three non migratory generations occur - then, in the Autumn the migration begins again and this is what I was pleased to observe at Cape May.

Researchers at Cape May are monitoring numbers to learn how varying environmental factors are influencing the migration. A standardised census count is made three time a day between September 1st and October 31st. Thousands of Monarch butterflies are tagged each year in Cape May. The tags consist of small pieces of coded adhesive paper place on the wing which does not change the way the butterfly behaves or flies. Monarchs are not slow during the migration, one butterfly tagged in Cape May was monitored in Georgia three days later - a distance of 558 miles.

Come the evening they roost in huge numbers.

Reproductive hormones are turned off for the duration on the migration - these are just good friends.

"My Monarch"

I had the opportunity to have a lengthy chat with one of the researchers and my burning question was about the genetic make up of the population. Occasionally Monarchs turn up in UK, where they come from is anyone's guess, whether arrival from west or east or the abhorrent "confetti" - who knows. However, I had imagined that these butterflies and those sedentary populations on the Atlantic Islands would have significantly different ancestry. The answer - they are all genetically identical - the mind boggles.

Many thanks to the staff at Cape May for the information on the Monarch and their patience with an inquisitive visitor.

Thursday 16 April 2020

Self Isolation - Part 4 Butterflies and Bees

This one is for Kevin

Firstly humble apologies to my 7 readers for being so tardy in producing part 4. When we started self isolation I thought it would be a doddle, just photograph stuff in  and over the garden. Well several weeks in and new material has become hard to find, the birds have thinned out looking for breeding sites. The long staying female Blackcap was joined briefly by a male and now both have melted away. One Jay is still visiting, no longer to cache peanuts but now on the prowl for the chance of eggs or nestlings. Our resident Blackbird pair, who have nested in the dense Bay tree next to the patio had a ding dong set to with the Jay and were struggling to drive it off, a rap on the patio door resolved the situation but I fear only temporarily. Jays are persistent nest robbers. In the front garden, two Robins have set up home, the male sits atop an ornamental birch tree and informs the world that this is "my patch".  

Another bonus of lockdown is that traffic noise has virtually disappeared and now I can hear birds that are much further away. The Wren who shares his presence over about six gardens was loudly  proclaiming his ownership of the territory and was being answered by at least two other birds. In the garden the other day I suddenly came up short as I realised I was listening to the faint far off strains of a Skylark - god knows how far away that would be as the nearest suitable habitat has to be at least a mile away.

The butterfly list has been extended by Large White, Brimstone, Holly Blue and several off course female Orange Tips. Speaking of off course - I was summoned by Liz to view a large butterfly sunning itself on one of the large plant containers on the patio. As always, I grabbed the camera but as I arrived the subject went airborne, did a lap of the garden and disappeared over the fence into my neighbour's extensive patch. My first UK Large Tortoiseshell. I stood in the garden ruing the fact that I had missed a shot when lo and behold the said butterfly reappeared, did another circuit of the garden and without pause disappeared forever. It would appear that there has been an influx of Large Tortoiseshells on the warm southerly winds, plenty of reports from Sussex to Suffolk.

Holly Blue


Plenty of Bees about, especially Grey-patched Mining Bees. The problem with photographing insects is that it takes fractions of a second to record the subject and several hours poring over the books to come up with, what in the end, is a best guess. Of course you could take the easy way out, stick it on Twitter and ask for an ID, sort of bypasses the reasons for having the book and adds little to your knowledge.

Grey-patched Mining Bee, Andrena nitida

Grey-patched Mining Bee, Andrena nitida

Grey-patched Mining Bee, Andrena nitida

Another Andrena??

Hoverfly - a Platycheirus??

Buff-tailed Bumblebee, Bombus terrestris

Buff-tailed Bumblebee, Bombus terrestris

Dark- edged Bee Fly, Bombylius major

Eristalis pertinax

Constant searching of the skies has revealed very little, today a fly over Buzzard at extreme height and precious little else. No sign of the White Storks that have been doing the rounds, nor of any hirundines. Ten vociferous Mediterranean Gulls flying high over added another bird species to the lockdown list