The British subspecies of Willow Tit (Poecile montanus kleinschmidti) is native to the UK and differs from its Eurasian counterparts in both its plumage detail and usual habitat preferences (Broughton et al., 2016). Willow Tits are non-migratory, staying in one area all year, and they like to live in early successional woodland and scrub habitats. They don't have noticeable differences between males and females and are slightly smaller than blue tits.

These birds can be hard to spot because they spend a lot of time in thick foliage. They have a small black bib and large cap, they are medium brown, with pale cheeks and have a light grey chest and lower portions. Identifying them can also be tricky as they look similar to Marsh Tits, especially since their appearance can vary slightly with age and other factors. That's why their voice is the most effective, impartial, and reliable attribute to identify Willow Tits.

Despite its widespread distribution throughout Eurasia, the Willow Tit is the second-fastest declining bird species in the UK, with populations declining by 96% between 1970 and 2021; short-term population data analysis also revealed a 47% decline between 2016 and 2021 (DEFRA, 2023).

They are now extinct in the majority of their former habitats in the south and southeast of England, having lost roughly half of their breeding range (Pinder and Carr, 2021). According to the national Willow Tit survey, Derbyshire is one of the top three ceremonial counties in terms of the number of Willow Tits recorded. However, records from both the Derbyshire Wildlife Trust's Derbyshire Biological Records Centre (DBRC) and the Derbyshire Ornithological Society (DOS) showed a 37% decrease in records obtained between 2022 and 2023. This demonstrates that, while the population of Willow Tits in Derbyshire is relatively robust when compared to other counties in the UK, they are still facing significant challenges and declining populations.

The presence of nesting Willow Tits is associated with the following six primary habitat characteristics:

• Habitat wetness (food source availability e.g. insect larval development) 
• Canopy height (1-4 metres) and structure (e.g. dense thickets and scrub)
• Vegetation species composition (Willow, Alder, Birch, Gorse, Brambles, Hawthorn, and Blackthorn)
• Nesting site availability (standing deadwood)
• Habitat size (7 ha per territory)
• Connectivity.

Possible reasons for the decline include habitat loss, lack of connectivity, habitat deterioration, nest predation, and competition from other bird species.

One objective of Derbyshire Wildlife Trusts’ ‘Nature-Based Solutions’ project was to conduct a Willow Tit recovery feasibility assessment of nature reserves within the Derwent Valley. Whilst also exploring wider considerations for Derbyshire as a whole, considering both biological and ecological characteristics of the species. The results of the study showed that the sites reviewed are currently not optimal Willow Tit habitat and require hands-on management to create preferred habitat. Overgrazing, habitat fragmentation, the management of young woodland maturation, a reduction in soil moisture, and the absence of deadwood nest sites are all habitat management concerns. These can be addressed and managed using various methods such as the implementation of ‘leaky dams’ to retain ground moisture, felling and coppicing of mature trees to maintain preferred canopy height and the planting of suitable vegetation such as Willow and Blackthorn.

To further our understanding of current viable populations across Derbyshire a passive acoustic monitoring initiative is being explored. This should aid in expanding our existing knowledge of where Willow Tits are in Derbyshire, in what capacity and how they utilise their territories.

Willow Tits are our fastest declining non-migratory bird in the UK and require action now. The project's next stages aim to identify established and reliable Willow Tit territories and manage the land to maintain the locations in ideal Willow Tit habitat. Secondly, verify the population size, distribution, and continuous presence of Willow Tits in regions where reports of sightings have been inconsistent. Finally, create links between the aforementioned locations and/or the central regions across the landscape.