The frequency and severity of heavy storm events is expected to worsen amid our changing climate. Heavy rainfall can cause flooding and infrastructure damage, devastating human communities around the nation. In the spring of 2019, floodwaters overwhelmed levees across the Midwest, causing billions of dollars of crop damage. Record downpours in Tennessee caused severe mudslides, and heavy precipitation in California damaged thousands of buildings.
Heavy rainfalls also impact birds and other wildlife in damaging ways. Increased precipitation and rising coastal waters can inundate shorebird nests and flood burrows, wash out eggs or kill chicks. Parental nest visitation rates also decline with increasing amounts of daily rainfall, with this effect becoming stronger after consecutive rainy days. Thus, rain during the nestling stage not only relates to fledging success, but also has longer-term effects on recruitment and subsequent parental survival.
For shorebirds like the Piping Plover and other species with precocial young that can feed themselves soon after hatching, heavy rainfall can impact chicks’ thermoregulatory and foraging abilities. This can lead to decreased chick survival. Outside of the breeding season, increased precipitation (in the form of snowfall) during winter could reduce food resources for birds overwintering in northern latitudes. For example, due to deeper and longer snow cover during harsh winters, small mammals are unavailable for hunting Barn Owls, leading to decreased survival of both adult and juvenile owls.
Rainfall-induced changes in seasonal bird behavior can also negatively impact species populations, especially those that are migratory. Annual variation in tropical rainfall and food resources are associated with substantial changes in the timing of spring departure for American Redstarts, while trans-Saharan migrants adjust their autumn migration timing according to temperature and precipitation effects. Rainstorms also tend to ground birds, preventing the start or continuation of long-distance migratory journeys.
Without immediate action, climate change is projected to increase the frequency with which birds have to weather heavy precipitation events. But we can help. Lowering carbon emissions will help slow global warming and reduce the risk that these birds will face. More immediately, you can make sure that birds have access to dry seed, keep extra-large capacity feeders for use in inclement weather, scatter seed in sheltered places, and provide bird houses both for breeding and during the off-season. You never know when a bird will need a shelter from the storm!
