Reports of a Monarch butterfly have been coming in.
- Swanage Castle 14/08/2107
- Durlston Castle area (Grid ref SZ 03/77) 13/08/2017
- Durlston 14/08/2017
- Durlston Castle area (Grid ref SZ03/78) 19/08/2017
It may be that there are only one or two individual specimens, being seen by different people.
Bill Shreeves, our Records Officer says:
The problem with Monarch records in August is that they are probably too early to be the genuine migrants which originate from USA when Monarchs are migrating down the east coast to reach their Mexican hibernation area. On their way down in late September-October they sometimes get caught up in high air currents which carry them across the Atlantic and along the UK coast, very often to Dorset.
Any Monarchs seen in August or earlier are very probably home-bred or released for the new fashion of butterfly weddings, where they seem to replace confetti.
We will be keeping a note of all records of Monarchs; if the reports come in from different areas, or we have evidence of bird or other insect migration from across the Atlantic around the same time we might revise our position.
Other research also supports the likelihood of these recently reported specimen(s) being releases and not from America:
When the late summer and early fall Monarchs emerge from their pupae, or chrysalides, they are biologically and behaviorally different from those emerging in the summer. The shorter days and cooler air of late summer trigger changes. In Minnesota this occurs around the end of August. Even though these butterflies look like summer adults, they won’t mate or lay eggs until the following spring. Instead, their small bodies prepare for a strenuous flight.
Monarchs in Spain (and in fact Florida) are non-migratory due to the warmer winters and tend to be continuously brooded.