What is it about?
Gulls have been expanding their breeding colonies to the urban centres as the coastal habitats change and the urbanisation increases. Gull chicks are thus good for biomonitoring urban contamination, as they are often feed with food/prey caught in the vicinities of the colony. Contaminants like heavy metals were already reported to affect the immune and endocrine system of wild seabirds, including gulls. However, there was a gap of knowledge on whether or not these contaminants could impact seabirds at early-life stages. Therefore, we assessed how mercury and other metals and metalloids (lead, arsenic, copper, iron, aluminium, selenium, etc) could be related to impaired physiological and health condition in urban-dwelling gull chicks early after hatching.
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Photo by Damla Özkan on Unsplash
Why is it important?
The proximity of gulls to humans in the cities turns them valuable samplers of urban contamination. Also, as top predators (like humans), gulls will provide a picture of what trace elements can be elevated in human tissues, and potentially, affect physiological and immune responses. We provide the first data on this research topic for resident gulls in Portugal, contributing to fill one more gap, that can be used for further meta-analyses.
Perspectives
I hope this work can contribute to make people more aware of what contaminants can be more prevalent and elevated in the cities. As the human population increases and the establishment of megalopolises increase in coastal areas, coastal seabirds are forced to adapt (or leave) to these novel ecosystems. Gulls are incredible and well-adapted seabirds that may tell us a whole story about the environment where they forage for prey, even though those places could overlap with ours.
PhD Ivo dos Santos
Universidade de Coimbra
Read the Original
This page is a summary of: Mercury and other trace elements in gull chicks from a highly urbanised environment: effects on chick growth, physiology, and health condition, Environmental Research, March 2026, Elsevier,
DOI: 10.1016/j.envres.2026.123701.
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