How Is Wildlife and Biodiversity Affected by Urban Expansion?

How Is Wildlife and Biodiversity Affected by Urban Expansion?

Last Updated on by Catherine Tobsing

The expansion of urban areas poses a significant risk to biodiversity, yet understanding how wildlife adapts to such rapid environmental changes remains limited.

The COVID-19 pandemic, characterized by widespread lockdowns that drastically reduced human activities, offers a rare insight into wildlife adaptation mechanisms.

Through analyzing over 126,000 bird observations collected via a citizen science project in northeastern Spain, we investigated birds’ adaptation during the spring 2020 lockdown.

Contrary to expectations that birds would occupy deserted urban spaces, our findings showed no increase in their urban presence.

However, we observed heightened bird detectability, particularly in the early morning, indicating a swift adjustment in their daily routines to the quieter, less populated cities.

This adaptability highlights the behavioral flexibility of urban birds in responding to new environmental circumstances imposed by the pandemic.

COVID-19, behavioral adaptability, urban ecology, observation techniques, community science – Introduction:

Since the inception of human settlements, transforming natural landscapes into urban areas has been a defining trait of civilization, with urbanization accelerating globally over the past century.

This shift poses a major challenge to biodiversity, as urban environments present numerous obstacles to wildlife, from pollution to human interference.

Despite this, some species manage to thrive in cities, raising questions about their adaptation strategies.

The distinction between phenotypic adaptation ( the change in the appearance of organisms due to genetic mutation or in response to the surrounding environment),  and evolutionary changes, however, is complex and understudied, especially in the context of urban settings.

The unforeseen social experiment triggered by COVID-19 lockdowns, resulting in significantly reduced human presence, provides a unique framework to study wildlife adaptation to urban environments.

Material and Methods:

Following Spain’s lockdown announcement in March 2020, we launched a citizen science initiative to collect data on birds’ responses to the altered urban landscape.

This period of reduced human activity allowed for a comparison of bird observations with historical data from 2015-2019, focusing on urban and non-urban settings.

We analyzed the presence and detectability of 16 common urban bird species, adjusting for factors such as time of day and survey duration.


Our study revealed that the lockdown did not lead to a significant increase in bird presence in urban areas.

However, detectability improved, with a notable increase in the early morning hours.

This suggests that birds quickly adjusted their routines to the newfound quietness of cities, a behavior more akin to their non-urban counterparts. These findings underscore the importance of considering temporal patterns in urban wildlife studies and highlight the potential of adaptive behavior in response to sudden environmental changes.


The lack of a significant increase in urban bird presence during the lockdown challenges the notion that wildlife rapidly reclaims human-dominated spaces when human activity wanes.

Instead, the observed changes in bird detectability point to a remarkable behavioral flexibility, allowing urban birds to quickly adapt to less disturbed conditions.

This behavioral adaptability, likely facilitated by previous exposure to fluctuating human activity patterns, suggests that urban wildlife may have a greater capacity to cope with environmental changes than previously thought.

Our study also emphasizes the value of citizen science in gathering extensive wildlife data and highlights the potential impact of urban lifestyles on wildlife behavior and conservation efforts.

Presented by Mitch Rezman and the Windy City Parrot Content Team

Mitch Rezman

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