Little Ringed Plover breeding attempt: epilogue

Little Ringed Plover (Charadrius dubius)

The ill-fated breeding attempt by Little Ringed Plover (Charadrius dubius) on La Palma, described in my previous post, has had at least one positive spin-off...

Once it was clear that the shorebirds were about to breed, I alerted the island's Environmental Authorities to the critically low water-level in the pond. Only a tiny puddle remained, bordered by a patch of damp sand, and it seemed a good idea at the time to try and improve the conditions and  prevent the artificial habitat from drying up completely.

The authorities promptly responded by agreeing to send a tanker truck containing 6,000 litres of untreated water which was pumped into the irrigation pond two days later, on the morning of May 19, after obtaining permission from the owner. 

Unfortunately, by that time it was too late to save the brood of plovers, but a useful resource has been created for both resident and migratory species, until the water eventually evaporates. The Environmental Authorities might agree to topping up before summer, I was informed by an insider source.

The following images give an idea of the operation as it unfolded on May 19:

Water tanker (left) pumping water into the dried out irrigation pond.

View from the eastern end of the pond, as the pool gradually grows in size.

All 6,000 litres have now been pumped in.

The finished "wetland"...

My thanks to the Environmental Authorities for their efforts and expense.

Breeding attempt of Little Ringed Plover on La Palma

Little Ringed Plover (Charadrius dubius)

The Little Ringed Plover (Charadrius dubius) is a resident breeding species on Tenerife, Gran Canaria and Fuerteventura, and a passage migrant to the remaining Canary Islands. During breeding it favours freshwater reservoirs with sandy edges, but also near golf courses with ponds, and gullies with running water (Birds of Macaronesia Eduardo García-del-Rey, Lynx Edicions).

On La Palma, the species can occasionally be observed during migration periods both at the saltpans in Fuencaliente and at the freshwater irrigation ponds in Las Martelas (Los Llanos de Aridane). The possibility of it sporadically breeding on islands other than Tenerife, Gran Canaria and Fuerteventura is postulated in the Atlas de las Aves Nidificantes en el Archipiélago Canario (various authors, SEO/Birdlife). The following account constitutes - to the best of my knowledge - the first documented case of a breeding attempt on La Palma.

I first observed the future breeding pair in an irrigation pond in Las Martelas (Los Llanos de Aridane) on March 21, but it wasn't until April 16 that the birds really attracted my attention. As the following images show, by then the two birds were in the process of mating, and nest preparation was already underway. 

 

Mating and nest building April 16

Mating and nest-building April 16

Breeding pair of Little Ringed Plover (Charadrius dubius), La Palma April 16

The plovers had chosen an inconspicuous sandy patch in an almost dried-out pond: less than idyllic surroundings perhaps, but despite its proximity to a busy lane, the pond is effectively screened from both traffic and passersby. One side of the pond ajoins a banana plantation and has no access, while the other side is skirted by a dead-end track, only used by the occasional farm vehicle. Whatever human activity I witnessed in the vicinity barely affected the birds' behaviour.

The nest site was located at the far (eastern) end of the pond, bordering the darker materials.

Sometime between April 16 and April 24, the female laid her clutch, and on April 25 the two birds could be seen taking turns incubating initially 3, then finally 4 eggs, countable whenever one of the pair briefly left them uncovered. All photography and observation was carried out with the utmost care from a considerable distance, using available bushes for cover to avoid disturbance.

Incubation of the clutch of 4 eggs. Photo taken through bushes of Tree Sorrel (Rumex lunaria) at far (eastern) end of pond.

Centre: the clutch of 4 eggs momentarily exposed during a short absence of the brooding bird. Left click on any image to enlarge.

By May 16-17 all 4 eggs had successfully hatched, and both adults could be seen accompanying the precocial chicks as they foraged. Most of the time the family group stayed away from the wet patch found on one side of the pond, preferring to explore the dry sand. I witnessed neither threats from potential predators such as kestrels, gulls, cats, dogs, or rats during my daytime visits, nor human interference of any kind. Everything seemed to be going smoothly, and the breeding pair turned out to be attentive parents.

Little Ringed Plover (Charadrius dubius) with one of her chicks.

Little Ringed Plover (Charadrius dubius) with all 4 successfully-hatched chicks. Not easy to see! Try left-clicking on image.

The 4 successfully hatched chicks foraging. At least one of the parents was always close by, keeping an eye on them.

Little Ringed Plover (Charadrius dubius) on the upper rim of the pond, trying to shepherd the chicks to a safer location

On the morning of May 18 only 2 of the 4 chicks could be seen, and to my surprise the parents were trying to usher them out of the pond. This seemed like an impossible feat for the flightless hatchlings, the banks of the pond being steeply sloping concrete. Through insistent calling and shepherding the parents somehow persuaded their progeny to climb to the top. Unfortunately, the obstacles to further progress proved beyond their capabilities, and the chicks had to clamber back down again. What was going on? I returned to the pond later and, by the time I left at about 19:30, everything had apparently returned to normal and both parents were settling down for the night with their 2 offspring.

Parent ushering her chick up the steep banks of the pond

The two chicks make it to the top but are unable to go any further

One of the 3-day-old chicks contemplating the descent

The same very vulnerable chick mid-descent. 

 

The following morning, May 19, all the chicks were missing and both parents were searching and calling for them. The female was still scanning the pond from the neighbouring greenhouse roof when I left the site in the early afternoon. It seems their brood had been preyed on during the night...the most likely culprits being rats or cats. No feathers or other remains could be seen. On May 18, the adults had probably taken the risky decision to move their family elsewhere after losing two of their chicks to nocturnal predators, but their plan had unfortunately proved unfeasible.

The first documented breeding of Little Ringed Plover (Charadrius dubius) on La Palma had thus been unsuccessful, but this resilient species is known to make further attempts during the same season after brood failure. Monitoring of the area will continue: let's hope for better luck next time.