Hampshire and Isle of Wight Butterfly and Moth Society
Hampshire and Isle of Wight Butterfly and Moth Society
| Family: | Papilionidae |
| Subfamily: | Papilioninae |
| Genus: | Papilio |
| Species: | machaon |
| Authority: | Linnaeus, 1758 |
The Swallowtail is our largest native butterfly, and also one of our rarest. This spectacular insect is our only resident butterfly of the Papilionidae family, which is one of the largest butterfly families in the world. The British race is the subspecies britannicus which is confined to the fens of the Norfolk Broads in East Norfolk. This is partly due to the distribution of the sole larval foodplant, Milk-parsley. Seeing the adult butterflies flying powerfully over the Norfolk Broads is a sight to behold, and one near the top of the list of most British butterfly-watchers.
In some years, there are reports of the gorganus subspecies arriving from the continent. This subspecies is less fussy and will use many kinds of Umbellifer, such as Wild Carrot, as the larval foodplant. 2013 was an exceptional year for this subspecies, with sightings from 13 sites across Hampshire, Sussex and Kent, and a single site in Buckinghamshire. These sightings included evidence of egg-laying and the resulting larvae and pupae have been followed through to spring 2014. On April 14th 2014 a single continental Swallowtail was seen and photographed at the Magdalen Hill Down Butterfly Conservation reserve near Winchester in Hampshire.
| #Individuals | #Tetrads | 2023 | 2024 | Abundance Trend | 2023 | 2024 | Distribution Trend |
|---|---|---|---|---|---|
| 0 | 3 | N/A | 0 | 1 | N/A |
| #Records | #Individuals | Earliest Record | Latest Record | |
|---|---|---|---|---|
| All Records | 3 | 3 | ||
| 2024 | 3 | 3 | 22/6/2024 | 28/9/2024 |
| Location | Date | Quantity | |
|---|---|---|---|
| Earliest Record | Gosport | 22/6/2024 | 1 |
| Latest Record | Gosport | 28/9/2024 | 1 |
| Highest Count | Gosport | 0/0/2024 | 1 |
One of the issues with 'raw' trend data is that there is inherent bias based on the number of recorders. For example, the number of individuals and populated tetrads recorded are likely to increase if there is an increase in the number of recorders. In order to remove this bias, the normalised trends use data that has been recalculated using the average number of recorders over the trend period. This normalisation gives a much better picture of the true trends.
Average #Recorders: 0.12
Average #Recorders: 0.12