The present post offers a summary of the breeding attempt, evaluates the actions taken, and raises a number of questions. Click on the following links to follow the whole story:
PART 1
PART 2
PART 3
PART 4
Chronology of the key events:
May 22: breeding pair first observed in irrigation pond.
May 24-28: courtship and nest preparation.
May 30: nest with 1-2 eggs. Incubation begins.
June 3: nest with at least 3 eggs.
June 4: nest with full clutch of 4 eggs.
June 26: first hatchling observed in the morning.
June 27: first hatchling observed in the morning.
Total of three chicks observed in the afternoon.
July 17: only 2 chicks observed from morning onwards.
July 18: only one chick observed from early morning onwards.
July 23: last remaining chick observed in the late afternoon.
July 24 - 30: unaccompanied adult female observed on July 24, 28 and 29. Thereafter, no birds present.
Conservation measures and threats:
The Environmental Agency delivered 8 tankerloads of water altogether, on a weekly basis from June 8 onwards. This was undoubtedly a vital contribution to the birds' survival, as no other suitable habitat was available at the time.
An attempt was made to minimise the threat posed by the nearby cat colony. The Environmental Agency negotiated with the relevant animal protection group. The exact number of felines in the colony was unknown, estimates ranging from 6, to as many as 15 individuals.
Trapping was attempted but encountered legalistic and operational impediments, and only 4 animals were removed from the area. Throughout the chick-rearing period cats were regularly observed in the vicinity, although none actually in the bottom of the reservoir, with the sole exception of the individual photographed on June 3.
That said, my monitoring was restricted to daylight hours, for periods of up to two hours maximum. The only exception was on July 18 when I stayed at the site until after midnight, without detecting any nocturnal threats to the plovers.
Flight capacity and doubts surrounding dispersal
Wing-exercising, upward propulsion, short glides, and brief low flight within the reservoir are documented in PART 4. At no time did I see any of the chicks try to fly out of the reservoir, or reach the top of the surrounding walls. I was expecting to witness trial flights of some duration/altitude before the birds' final dispersal, but they never materialised in my presence. The last fledgling simply disappeared at an age of 26-27 days.
At no point did I observe friction between the adult female and any of the chicks due to competition for resources. On the contrary, there seemed to be a close bond between parents and offspring throughout the rearing period.
My question is: do Little Ringed Plovers normally disperse in this manner, suddenly abandoning their territory at a given moment, never to return, as soon as they feel strong enough? It strikes me as highly unlikely, but I would appreciate comments from observers with experience of this species.
What happened to the chicks?
Fortunately, I noted down the approximate times of my observation sessions, and digital photographs likewise provide details.
The first chick disappeared sometime between 11:00 July 16 and 09:30 July 17, at an age of 20-21 days. It could therefore have been taken by either a diurnal, or a nocturnal predator.
The second chick disappeared sometime between 21:40 on July 17 and 07:30 on July 18, at an age of 21-22 days. It almost certainly fell victim to a nocturnal predator.
The third chick disappeared sometime between 20:15 on July 23 and 10:00 on July 24. It could have theoretically been caught by either a diurnal or a nocturnal predator, though the latter seems more likely. Otherwise, it could have voluntarily flown away, never to return, at an age of 26-27 days.
Diurnal predators:
The only realistic candidates are cats and Common Kestrels (Falco tinnunculus). As noted in PART 4, kestrels were frequent around the nesting area. Common Kestrels were formerly held in low regard by henkeepers on the island, as these raptors predated on flightless chicks.
The adult plovers used a high vantage point on the reservoir rim, or on the roof of an adjacent greenhouse to keep a lookout. Any approaching kestrel was harassed and driven out by one or both of the adult plovers. Despite their efforts, it is possible that the first and third chicks were caught unawares at some point.
Other daytime avian predators such as gulls, corvids, sparrowhawks or Barbary Falcon can almost certainly be discounted for various reasons.
Nocturnal predators:
The most likely candidates are cats, whose presence was more or less constant in the area.
I have never seen Long-eared Owls (Asio otus) in this particular area, but the species is widespread on the island, even in urban surroundings.
Rats are generally believed to shun open areas, such as the exposed beds of irrigation ponds.
Thus, all three chicks could theoretically have been taken by nocturnal predators. As regards the disappearance of the second chick, nocturnal predation is almost certain, while for the third chick, it is more likely than diurnal. The first chick could have been taken either by day or night.
Several key questions unfortunately remain unanswered:
Did any of the chicks, especially the third one, survive and successfully disperse of their own accord?
Is the Common Kestrel (Falco tinnunculus) capable of preying on 20-27 day-old chicks which are already able to run fast and almost fly?
Do Long-eared Owls (Asio otus) hunt in this area?
