PatchBird  
Nocturnal

These maps offer an early view of the records I (Gyorgy Szimuly) have collected while developing PatchBird Nocturnal. They show how observations from individual visits can build into a picture of recording activity across different locations—and make those records available for everyone to explore.

​

This is a visual presentation of collected data, not a scientific analysis. The dataset combines casual observations and stationary counts made using methods that have developed over time. Visit duration, recording conditions and the frequency of visits vary between locations. The maps, therefore, cannot establish owl abundance, population trends or differences in habitat quality.

​

How to read the maps

 

Use the species switch to explore Tawny Owl or Western Barn Owl. The record-type switch lets you view "All records", "Casual/incidental observations", or "Stationary counts".
 

Changing either selection updates the locations, colours and pop-up summaries. Click or tap a circle to see its UTM location name, selected record type, total recorded visits, visits with a detection and date range.

• Grey circles indicate locations with zero counts and no positive record of the selected species within the chosen record type. Zero counts are included only for stationary counts.

• Orange-to-red circles indicate at least one detection. Darker colours represent more visits with a detection, not more individual owls. The darkest shade represents six or more detection visits.

• All circles are the same size. Size does not represent visit frequency, survey effort or bird numbers.

• Where the selected records contain both detections and zero counts, the location appears coloured.

​

The same colour scale is used for both species.

​

Why the record type matters

​

Casual or incidental observations record species encountered without a complete checklist. If an owl species is not listed, that does not mean it was searched for or was absent. Missing species on these checklists are therefore not assigned zero counts. The casual-record view shows detections only.

​

Stationary counts can include both detections and zero counts. Some zeros were recorded originally; others were added during database preparation based on checklist-completeness assumptions. These derived zeros should not be interpreted as independently confirmed non-detections.

​

Stationary counts also vary in duration and method. Selecting this category does not mean that every included visit followed the same standardised survey protocol.

​

What these records can — and cannot — tell us

 

An owl may be present without being seen or heard during a visit. A grey marker therefore indicates no recorded detection within the selected records, not confirmed absence. Places without markers should not be interpreted as places without owls either.

​

The spread of records reflects where I have had opportunities to observe. My work has enabled extensive travel and recording across Britain in recent years, but coverage remains uneven. Some locations have been visited repeatedly, while others have only a single record. More detection visits may reflect more opportunities to observe, rather than a greater number of owls.

​

Wider participation can help extend that coverage, particularly through consistent, repeated visits.

​

A starting point for participation

 

The purpose of this presentation is to make the developing dataset visible and demonstrate how individual contributions can become a shared resource. Both detections and properly documented non-detections have value when their recording context is understood.

​

As PatchBird Nocturnal develops, standardised recording will provide a stronger foundation for future analysis and, potentially, better-informed conservation decisions. For now, these maps share the observations gathered so far and invite others to take part.

​

This demonstration includes records from 7 May 2024 through 24 October 2026.