Four incidents of weapons being used on wildlife were recorded in Pembrokeshire between 2020 and 2023.
The figure is set to rise as an incident this year involved a hedgehog in Haverfordwest, which was found with an air gun pellet embedded in its shoulder.
The injury was so severe that the hedgehog had to be put to sleep on welfare grounds in April 2024.
Also in Wales, a swan in Tredegar was found to have a pellet in his head whilst officers were investigating fishing litter lodged down his neck and fishing line around his leg. He also had to be put to sleep.
Overall, the RSPCA recorded 896 incidents involving air weapons across England and Wales from 2020 to 2023, with 66 of these reported in Wales.
RSPCA lead wildlife officer, Geoff Edmond, said: "Weapon attacks are horrific, but what we see is likely only the tip of the iceberg.
"It is unspeakably cruel and totally unacceptable to shoot animals for ‘fun’ like this - or to harm them for target practice, and sadly we receive too many reports across Wales."
The RSPCA's warning comes as part of their 'No Animal Deserves Cruelty' summer campaign.
The charity has seen a 23 per cent year-on-year increase in the total number of animals targeted by weapons across England and Wales, rising from 300 in 2022 to 370 in 2023.
Crossbows are the weapon which has seen the biggest increase in its use in attacks, with 11 incidents in 2023, compared to seven in 2022.
Mr Edmond added: "Day after day, our frontline officers and animal centres see the sickening consequences of weapons being used on animals - severe injuries often leading to death.
"And what we deal with probably only represents a small part of a much wider problem, as not all cases will be reported to the RSPCA directly and there may be situations where animals injured and killed by these weapons are sadly never found - especially in the case of wildlife."
The RSPCA has launched its RSPCA No Animal Deserves Cruelty Appeal because it receives more reports of cruelty in summer than at any other time of year.
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