Heatwave 2026: When wild animals die of thirst and hobby hunters shoot anyway

Switzerland is sweating. The first major heatwave of 2026 is bringing up to 38 degrees in places, and meteorological records for the month of June are at stake. For people there is air conditioning, open-air pools and time off due to heat. For wild animals there is no emergency exit.

What heat does to wild animals

Startled wild animals expend energy in flight reactions and afterwards have to lower their body temperature again. As a result they grow thirsty even faster and must set off in search of a watering place.

The problem: these very watering places are drying up. During prolonged drought, wild animals face dehydration, heat stress and, in extreme cases, increased mortality – especially among young animals. Birds, hedgehogs, foxes, but also larger wild animals such as roe deer and red deer are affected.

On top of this comes a systemic problem: water temperatures in the Rhine and in the Alpine lakes are rising continuously. The Swiss Federal Institute for Forest, Snow and Landscape Research (WSL) has developed an early warning system that can assess the heat risk for fish populations at over 50 sites up to three weeks in advance. Once the temperature threshold for a species is reached, the fish's performance declines – particularly due to a lack of oxygen in the overheated water. This also reduces their ability to evade dangers.

Fish limited in their ability to react. Dehydrated foxes. Exhausted roe bucks. These are not marginal phenomena, this is the ecological reality of this heatwave.

More on how wild animals generally cope with extreme heat and what particular risks climate change poses for Alpine animals we have described in earlier articles.

And of all times, this is when the roe deer rut begins

The heatwave coincides with one of the most intense events of the wildlife year. The roe deer rut begins in mid-July and lasts until mid-August. Roe bucks are then hormonally at full throttle, cover long distances, barely feed and lose considerable body weight. In roe deer, thermoregulation occurs primarily through panting and behavioural adaptation – in the heat, roe bucks are therefore more dependent than usual on water and thermal retreats.

What hardly anyone knows: over the millennia, the roe deer has tuned its entire reproductive cycle to precisely this window of time. After mating in high summer, the fertilised embryo does not implant in the uterus immediately, but enters a so-called germinal rest – the embryonic diapause. This lasts more than four months until December. Only with the winter solstice does the actual embryonic development begin. The fawns are then born in May or June, when the food supply is at its richest. Researchers at ETH Zurich have studied this mechanism in detail; among antler-bearing animals it is considered largely unique. Nature has thus developed a highly precise mechanism so that fawns get an optimal start in life. Hobby hunting intervenes precisely in this mechanism – right in the middle of the phase in which the roe buck is at its most vulnerable.

In most Swiss cantons with a territorial hunting system, roe bucks may already be killed from May onwards. From mid-July to mid-August, when the rut is at its peak, hobby hunters practise so-called calling hunting: using a so-called “Blatter” – a mechanical luring instrument with a metal tongue – they imitate the bleating calls of a roe doe ready to mate, in order to lure the buck out of cover and kill it from a short distance. Electronic luring devices with recorded animal sounds are largely banned or heavily restricted in Switzerland; the mechanical “Blatter”, on the other hand, is not regarded as a prohibited aid within the meaning of the federal hunting ordinance. An animal that is already impaired in its responsiveness by rutting stress and heat stress is additionally lured out of the protection of cover with luring stimuli. Hobby hunters call this proper huntsmanship. From an animal welfare perspective, it is the deliberate exploitation of a biological state of emergency.

Why heat changes hunting ethics

The WSL warns: once the temperature threshold for certain fish species is reached, they can barely respond to dangers any more. The fishing sector therefore has closed seasons and, in extreme cases, mandatory intervention by the authorities. The principle behind this is clear: when environmental conditions acutely increase the vulnerability of an animal species, the rules governing its use must be adapted. For the hunting of terrestrial game – even though the same logic applies – such temperature-based thresholds are entirely absent.

This is a contradiction that Swiss hunting legislation urgently needs to address: if it is known that animals are particularly vulnerable during periods of acute environmental stress, why does this not count as grounds for a temporary halt to hunting?

Anyone wishing to understand the current hunting legislation in Switzerland and the need to reform it will find extensive documentation on wildbeimwild.com.

Climate change and hobby hunting: a double threat

Climate change poses a serious threat to wild animals in the Alps, particularly to marmots and ptarmigans. Marmots can barely actively regulate their body temperature and rely on cool burrows in the heat – a strategy that works as long as the nights stay cool. During prolonged tropical nights it fails.

Wildlife populations that already suffer under climate pressure do not need additional hunting during periods of acute environmental stress. They need rest, functioning habitats and watering places. That, of all times, it is precisely during heatwaves that hobby hunters head into the forest with lures and high seats is not nature conservation but its opposite.

A growing body of scientific evidence shows that extreme weather events such as droughts and heatwaves considerably limit wild animals' ability to respond to dangers. This concerns not only wildfires and climate change in general, but also recreational hunting in particular: a stressed, dehydrated animal whose responsiveness is impaired is not a legitimate hunting target. It is an animal robbed of its natural defensive capacity.

What you can do

If you want to help wild animals during this heatwave: place shallow bowls of fresh water in the garden or on the balcony, change it daily, and put a stone in the water as a landing aid. Keep your distance in the forest and do not startle any animals. Keep dogs on the lead.

If you want to become politically active: support the Campaigns by IG Wild beim Wild for a modern wildlife protection law in Switzerland.

And anyone who wants to know what the heatwave means in concrete terms for our waters and fish populations will find further background on wildbeimwild.com.