As autumn progresses, closely observing "our" lapwings ensures we’re far from bored. Five of them have moved to the Iberian Peninsula (with Prskavka even crossing into Portugal), others have shifted to the French coast of the Bay of Biscay, and even Drahuš—who had been notably hesitant to migrate and lingered in Eastern Bohemia with a group of nearly 30 lapwings—has finally decided to move. According to the latest data, she is near Munich. It will be fascinating to see where she ultimately heads, as she’s flying the furthest south among all the lapwings. Unfortunately, she’s currently experiencing some issues with her transmitter battery, so we might have to wait a bit longer for more detailed migration updates. For now, let’s leave the analysis of lapwing wintering grounds and the lessons learned from autumn migration tracking for a December blog.
Instead, today we turn our focus away from lapwings to the an interesting findings sent to us—albeit now mostly silent—from woodcock transmitters. One advantage of our woodcock research is its multi-year span, starting even before this year’s grant project. Similar to our work on lapwing incubation, we can rely on a longer dataset. Since 2021, we’ve been monitoring woodcock using GPS-GSM dataloggers, beginning with tagging seven males across three locations (Brdy, Ralsko, and Písecké hory). Our objectives were ambitious: tracking woodcock movements within their habitats, identifying their preferred environments, and mapping their migration routes to wintering grounds. We also hoped to detail the timing, routes, and duration of male display flights. There was even some optimism that male monitoring might help locate nests, as British researchers suggested that successful courtship could lead to males temporarily halting roding to remain with a female near their future nesting site (Hirons, 1980).
In theory, the used technology could allow us to observe all this—if only we worked with a species more amenable to open habitats. However, the woodcock’s penchant for dense undergrowth quickly and effectively dashed many of our plans. Tracking detailed roding flights or documenting “honeymoon” stays with a mate has remained a dream. We’re typically grateful if a tagged male communicates for a few weeks before its transmitter battery dwindles. Still, the data we’ve collected has revealed significant aspects of woodcock behaviour previously hidden from view.
One major discovery was the extent of woodcock movements during the breeding season. By creating polygons that encompass 95% of recorded transmitter locations (using the Minimum Convex Polygon method), we found substantial range sizes. On average, the monitored woodcock ranged over an area exceeding 7 km2, and in one instance, up to 54 km2 (Sládeček et al., 2023). Even 7 km2 is approximately 12 times greater area than the average home range found by British researchers monitoring woodcock via telemetry (Hoodless and Hirons, 2007). Why the difference? While we can only speculate, it’s likely tied to the much larger forests in the Czech Republic, compared to the smaller wooded areas of the English countryside.
Swiss researchers (Mulhauser and Santiago, 2006) observed highly uneven activity distribution among roding woodcock males in extensive forests, with roding males flying over some areas while neglecting others. Studies also reveal that males alternate roding sites between days (Hirons, 1980). Our data aligns with these findings. Significant movements (often 1–2 km) within their home range typically occurred either in the evening or just before dawn. Notably, woodcock also display in the morning, although this behaviour is less well-studied. It seems plausible that a male might relocate to another display site if no females were encountered, preparing for a fresh evening display.
The main value of telemetry lies in understanding woodcock habitat requirements. To this end, we visited 738 locations, describing the vegetation structure and species composition in detail (Sládeček et al., 2023). About half of these sites were previously visited by tagged woodcock, while the other half were randomly selected control sites. Comparing these two groups allowed us to identify vegetation types and characteristics preferred—or avoided—by woodcock.
So, what kind of environment does a woodcock need to thrive? Essentially, it must meet three key requirements. The first is an ample food supply. It’s therefore unsurprising that woodcock prefer certain types of deciduous forests, especially birch stands, which generally provide an abundance of earthworms, their primary food source. The second requirement is shelter from aerial predators. Woodcock make use of areas with sufficient herbaceous and shrub cover, often settling for dense young pine stands. While these habitats may not be particularly rich in food, they offer significant safety. The third requirement is that the vegetation must allow easy traversability. It’s important to note that woodcock forage on the ground. As a relatively clumsy bird, the size of a pigeon with short legs, it avoids pushing through dense undergrowth such as blueberry. This is why blueberry is among the vegetation types woodcock tend to avoid (Sládeček et al., 2023).
We also considered the time of day (day vs night) in our habitat analysis. While most habitat preferences were consistent, canopy density showed notable variation: woodcock frequented denser canopies during the day, but more open areas at night. Initially, we assumed that woodcock ventured into open areas at night for feeding. However, newer accelerometer-enabled transmitters (Interrex), which record activity every 10 minutes, revealed a surprising result. Contrary to expectations (and contrary to results of some studies, e.g., Brana et al., 2013), woodcock were mostly inactive at night, likely feeding almost exclusively during the day (Fig. 1a). In contrast, lapwing activity patterns were less distinct (Fig. 1b).
Despite the challenges of studying such a cryptic species, telemetry has provided valuable insights into woodcock behaviour and habitat use. We’re optimistic that future data will uncover even more intriguing details, which we’ll be eager to share in upcoming blog posts!
Figure 1: Typical activity (ODBA) for 48 hours in a male woodcock, Turbo (a), and a female lapwing, Kikina (b). The lower panel shows corresponding temperature, light levels, and battery charge for Kikina.
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