The breeding season is slowly entering its final third. Some lapwings are still attempting last nesting attempts, and Nerea has kicked off this year's migration by heading to Germany on June 13th – 16 days earlier than last year – and has already crossed into the Netherlands. Unfortunately, several more transmitters have failed, including Belinda's and Kikina's. This issue has even affected some newly deployed transmitters: Pipi went silent after relocating to Poland for a few weeks, Šmoulinka after moving from eastern Bohemia to the wet meadows and stable willow stands of the Třeboň Basin, and Ťapka for no obvious reason. Kraken was caught by an unknown raptor, which managed to carry him about 3 km from the field to a forest clearing, where the damaged transmitter was later found on a stump. And finally, Ďoura suffered a fate similar to last year's Cácorka, likely struck by a vehicle.
Even more dramatic than the loss of individuals is what can be observed on the nest success counter on our website map, showing the tragic rate of families raising fledged chicks. So far, only Andreska and Trinity have managed that feat. Sure, there's still time (and current data indicate that 11 lapwings are caring for at least one chick), but the list of families whose nesting ended before a single chick could take flight is sadly long this year.
The topic of today's blog is therefore quite clear: we'll take a detailed look at the lives and challenges of lapwing chicks. Just like in the previous blog about threats facing embryos inside eggs, the list of dangers awaiting chicks is far from cheerful. When a chick hatches, it weighs only 15 to 20 grams – about the same as two medium slices of ham. It has about a month to reach fledging age. While this might seem enough time to survive, it’s impressive that in this short span, the chick can multiply its weight up to tenfold.
A chick of Trinity safely hidden among poppies.
Teeth, Claws, Beaks!
Unsurprisingly, the first major concern for chicks is the multitude of predators trying to eat them, day and night. While nest predation is almost exclusively by nocturnal mammals in our region, chick mortality includes avian predators as well. Evidence from the Netherlands (Teunissen et al. 2008) and our own observations suggest birds of prey are significant threats. In one case, the only bird-of-prey victim we caught on camera during hundreds of recorded nest days was a chick wandering near hatching siblings, swiftly snatched by a kestrel.
Bent antennas on mini-transmitters also suggest chick predation by sharp-beaked birds, as if sliced like a ribbon by scissors. Chicks are easier for birds to grab and carry than eggs, especially since eggs are often covered by incubating parent. Cooperative defense among families would likely improve survival, but it's rare due to the high mortality of nests and chicks. However, some tagged females show attempts to raise chicks communally. Trinity, for example, fledged at least one chick in a poppy field alongside eight other lapwings that defended the area together.
Chicks aren’t entirely defenseless either. They can run surprisingly far, as well as hide effectively. In areas with scattered vegetation, this hiding strategy works well against predators. Much also depends on parental guidance and the chick's willingness to follow instructions. One observed chick refused to freeze on command, prompting its parents to repeatedly dive at it until it complied. Ideal chick-rearing habitat appears to be mosaic-like vegetation that combines good cover with open space for predator detection. While open areas offer visibility, vegetated patches provide better daytime shelter. Our observations this year favor the latter. Chick survival in bare fields has been notably poor. Suitable mosaic-like cover has been observed in poppy fields and even in atypical crops like soy.
When Predators Aren't the Only Problem...
Sadly, predators aren't the only threat. In April last year, we received reports of mass chick deaths due to sudden cold weather. Entire families of chicks just days old were found huddled together, dead. The culprit was clear: freezing temperatures, barely reaching 10°C by day and dropping to near zero at night (Fig. 2).
Figure 2: Temperatures and the resulting brooding needs of lapwing chicks during last April.Top: Hourly temperature progression in central Moravia – one of the areas where mass deaths of newly hatched lapwing chicks were observed.Bottom: Modeled brooding needs of Northern lapwing chicks for each day (see Kolešková et al., 2023).Dark gray parts of the bars represent time chicks needed to be brooded; light parts indicate time they could move freely and forage.
To better understand how chicks cope with weather, we studied lapwings parental care. Lapwing chicks are precocial – they leave the nest and feed themselves shortly after hatching. We've even seen newly hatched chicks swim across puddles. But they can’t regulate their body temperature for long. In cold conditions, they seek warmth under their parents (so-called brooding).
Using mini multisensory data loggers attached to chicks like tiny backpacks (Kolešková et al. 2023, Fig. 3), we collected unique data on behavior and heating needs. These loggers, weighing barely a gram, tracked movement, temperature, and light. When a chick was brooded under a parent, movement dropped, temperature rose, and light disappeared (Fig. 3a). Thanks to this technology, we learned how much time chicks of various ages need to spend warming up in different temperatures. While parental body heat remained effective even near freezing, the proportion of time chicks needed to warm up increased sharply. And the more time they spend warming up, the less time they have to feed – a serious issue for such fast-growing birds.
For example, at 20°C average daily temperature, a chick just a few days old might spend about 45% of the day warming (mostly at night), leaving 13+ hours for foraging. At 15°C, it still has around 10 hours. But at 4°C (as happened on some days last April, Fig. 2), it may manage less than three hours of active feeding. When combined with consecutive cold days, added energy costs from movement, and poor food availability, this can be fatal.
Figure 3: a) Example of data obtained by attaching mini multisensory data loggers to chicks' backs (see center photo). When the chick is being brooded, the temperature measured by the logger (thin red line) rises, while light levels and activity are low. b) A Northern lapwing brooding its chicks. c) Brooding of three chicks by a Red-wattled lapwing (Vanellus indicus). d) Chick of Red-wattled Lapwing with a multisensory data loggers.
Lost in the Jungle
One final, but significant, cause of chick mortality is impassable terrain. Not all places where chicks hatch are suitable for rearing. Though nearby suitable areas may exist, getting there isn’t always easy. Chicks can walk kilometers under good conditions, but if no safe route is found, the journey can end tragically.
Tracking with mini-transmitters has led us to the bodies of chicks trapped in dense sedge clumps while trying to cross overgrown ditches. These seemingly minor obstacles can be deadly for small birds, even if we wouldn't notice them at a glance. Improving landscape permeability from a chick’s perspective is therefore a vital consideration in lapwing conservation.
Next time, we’ll look at some specific journeys recorded via transmitters and try to imagine what it’s like to cross the late-spring countryside through the eyes of a lapwing chick.
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