Unusually high temperatures and drought levels this spring could have serious consequences for wild birds. Extreme heat during the breeding season threatens the reproductive success of species that rely on mud for nest building, such as swallows. SEO/BirdLife invites citizens to take simple actions to help birds cope with the heat.
Each swallow or sycamore nest is built from tiny mud particles carried in the beaks of busy parents. The birds scoop mud, mix it until smooth, and carefully remove air pockets before laying it down. Luis Martínez, a SEO/BirdLife technician at home, explains this process in detail.
The amount of mud a songbird can carry is limited. For example, a complete House Martin nest may require more than 2,500 mouthfuls of mud. The birds then make countless trips between their mud source and the nest, often more than 5,000 journeys across a two-week period to complete a single nest, as highlighted by the NGO during a focused study period.
When hundreds of nests are destroyed each year, whether legally or illegally, the lack of mud worsens the situation and disrupts the birds’ reproductive cycles.
Prolonged heat can cause young birds to leave their nests early, and if a nest is exposed to the sun, an exposed body and wings can create heat strain for the adults who must protect their chicks.
Physiological stress
Drought and reduced rainfall stunt vegetation growth and flowering, lowering the available resources birds rely on to survive water stress. Like humans, birds undergo significant physiological stress from heat. To cope, they need reliable water sources to rehydrate and refresh.
“The simplest way to help is to provide water in windows, patios, or gardens, using a container that is easy for birds to access, such as a shallow pan,” states SEO/BirdLife. They also point to places where mud is more readily available, like marshy areas, so that birds can gather the material needed to construct their nests without excessive energy expenditure on travel.
With water becoming scarcer, especially in urban areas, SEO/BirdLife stresses the urgency of making cities greener. “Public administrations should consider biodiversity in urban design and management,” says Beatriz Sánchez of the NGO’s Urban Biodiversity program. “Heat waves reveal how much cities depend on living systems.”
Nature Based Solutions
Nature-based solutions, or NbS, have been shown to be more effective and economical than conventional approaches in mitigating heat and related effects. Urban trees, for instance, can lower local temperatures by two to eight degrees, countering the heat island effect.
NbS are actions or processes that apply natural principles to address environmental challenges such as climate change adaptation, water management, food security, air quality, and ecosystem health. They promise cost savings and local job creation in addition to environmental benefits.
Living near green spaces also benefits people’s health. Studies indicate that access to nature in urban settings improves physical and mental well-being, and biodiversity richness correlates with life satisfaction in some populations.
“Greener cities benefit everyone, and this should be a consideration in electoral platforms and public policy,” Sánchez notes. SEO/BirdLife argues that the climate emergency makes it urgent to integrate more nature into urban environments, as cities bear substantial responsibility for biodiversity loss in the face of climate challenges.
Rethinking the urban model
Cities account for a large share of global greenhouse gas emissions. United Nations projections suggest that by 2050 two-thirds of the world’s population will live in urban areas, underscoring the need to rethink how cities are designed and managed. Large trees act as effective filters for air pollutants and fine particles, trapping them in leaves and bark and improving air quality.
Studies by major metropolitan authorities show that mature trees and expansive urban green spaces remove significant quantities of pollutants each year. Drought-affected landscapes and urban greenery influence water management, with mature trees able to regulate water flow and reduce flood risks by holding substantial amounts of water annually.
Nature also supports education. A growing body of research indicates that more nature in school environments improves cognitive performance and self-esteem, with improvements seen in working memory and attention in students. This aligns with broader findings about the social and emotional benefits of green spaces in communities.
Additional research highlights the importance of birds and biodiversity for human well-being. The broader literature emphasizes that birds serve as indicators of ecosystem health and urban resilience, underscoring why greener cities matter for people and wildlife alike.