Swallowtail (Papilio machaon)
Key Details
| Taxonomic Groups: | Invertebrate > insect - butterfly > Butterfly |
| Red List Status: | Vulnerable (Not Relevant) [VU(nr)] |
| D5 Status: | Included in the baseline Red List Index for England (Wilkins, Wilson & Brown, 2022) |
| Section 41 Status: | (not listed) |
| Taxa Included Synonym: | (none) |
| UKSI Recommended Name: | Papilio machaon |
| UKSI Recommended Authority: | Linnaeus, 1758 |
| UKSI Recommended Qualifier: | (none specified) |
| Red List Citation: | Fox & Dennis, 2021 |
| Notes on taxonomy/listing: | (none) |
Criteria
| Question 1: | Does species need conservation or recovery in England? |
| Response: | Yes |
| Justification: | GB Red List (Fox et al. 2022): VU. 51% increase in abundance since 1976 and a 9% short-term (10 year 2010-2019) decline; 26% long-term decline in distribution since 1996 and an 11% short-term decline (Fox et al. 2023) |
| Question 2: | Does recovery/ conservation depend on species-specific actions? |
| Response: | Yes |
| Justification: | Highly restricted distribution occurring only in the open fens and marshes of east Norfolk where its foodplant Milk-parsley (Peucedanum palustre) grows. Sub-species britannicus endemic here. |
| Question 3: | At a landscape scale, would the species benefit from untargeted habitat management to increase habitat mosaics, structural diversity, or particular successional stages? |
| Response: | No |
| Justification: | Highly restricted species with very specific habitat requirements |
Species Assessment
| Current step on the Species Recovery Curve (SRC): | 4. Autecology and pressures understood |
| Recovery potential/expectation: | Low - Combination or other (detail in comments) |
| National Monitoring Resource: | Structured - sufficient |
| Species Comments: | Combination of extinction debt and climate change. |
Key Actions
Key Action 1
Proposed Action: Research into the potential impacts of sea level rise and increased salinisation of sites where Swallowtail is currently found
Action targets: 4. Autecology and pressures understood
Action type: Scientific research
Duration: 3-5 years
Scale of Implementation: ≤ 20 sites
High priority sites:
Comments:
Key Action 2
Proposed Action: Carry out feasibility study to review areas of currently suitable and potentially suitable habitat where the species could be translocated, due to potential high risk of extinction if remains only in the current landscape.
Action targets: 5. Remedial action identified
Action type: Scientific research
Duration: 3-5 years
Scale of Implementation: National
High priority sites:
Comments:
Acknowledgment:
Data used on this website are adapted from Threatened species recovery actions 2025 baseline (JP065): Technical report and spreadsheet user guide (Natural England, 2025). Available here.