Meet the rufous hummingbird. It is one of the smallest birds on Earth and yet, it is about to start a great adventure. This journey will bring this little bird from the mountain woods in Mexico to the rainforests of Southern Alaska. But this five-thousand-kilometre trip isn’t important only for the hummingbird. It has a great impact on other living beings. During the journey, our traveller will make several stops. It will visit thousands of flowers looking for nectar, and it will end up transporting billions of pollen grains between plants, playing a key role in their reproduction. But the rufous hummingbird isn’t the only one. Many other migrant species, such as the monarch butterfly and the hummingbird hawkmoth also carry out this important task for the ecosystems! Regretfully, climate change is creating hazards like changes in rainfall patterns and temperatures that affect migration routes and dates and can lead to the uncoupling of many interactions these species are involved in. Humans also harm these habitats by modifying landscapes, adding artificial obstacles to migration routes. If this continues, migratory species won’t be able to make their vital impact on the reproduction of plants anymore. As the species living in an ecosystem are deeply connected and exist in a delicate balance, the disturbance of one has an indirect impact on the rest. If we want to conserve nature, we must protect migratory species!