Kilcoole Little Tern Conservation Project: The Wardens Duties

Aims of the Kilcoole Little Tern Conservation Project

Census the Little Terns & monitor their breeding success.
Maximise the breeding productivity of the terns by:

preventing disturbance caused by humans & dogs.
preventing the loss of eggs & chicks to predators.
minimising the impacts of storms & flooding where possible.

Liaise with the general public & media.
Carry out scientific studies on the terns such as:

Feeding ecology (observation).
Chick growth rates (weighing & measuring).
Dispersal & migration (ringing).

Project Methods

Censusing: Tern flock sizes are recorded on a daily basis. This is done when the terns take flight in response to disturbance (such as a warden entering the colony) or a predator (such as a Peregrine overhead). Flocks can also be counted during 'dreading' events. Dreading is when all the terns on the beach take flight & group together apparently in response to some unseen threat. It is thought however that dreading is actually a form of social bonding.

Monitoring Breeding Success: During the build up to the first eggs being laid (usually in mid-late May), behaviour such as pair bonding, courtship, display & nest site section is monitored. Once a nest with eggs has been located, it is marked using a code written on an upright stone positioned c.1-2m in front of the nest. This allows wardens to locate the nest site using binoculars or telescopes from a nearby path, even when the bird is not present. Using this method, wardens can monitor the nests from a distance that does not disturb the terns and ensure they are still present & incubating their eggs. The position of each nest on the beach is also recorded so a map of the colony can be created.

Little Tern on a nest with a coded marker stone © Niall Keogh

When a new nest is found, the number of eggs in it is recorded. Little Terns stagger their egg laying, with a new egg appearing every second day or so until 2 or 3 eggs are laid. If a nest with only 1 or 2 eggs is found, it is checked daily until the number of eggs hasn't changed over a 3 day period. The nest is then left alone until 18 days later (usually mid-June) when signs of hatching are checked for. This typically involves looking for cracks in the eggshell or listening for 'peeping' chicks inside, a sure sign that they are due to hatch at any stage. The nests are then visited daily until all the eggs have hatched. Sometimes one or all of the eggs may not hatch due to infertility. Normally if 2 out of 3 eggs hatch then the remaining unhatched egg will be incubated for a couple of days by the parent birds before being abandoned as they begin to move their young towards the foreshore. Rarely a whole clutch may be infertile, but they are however given 'the benefit of the doubt' for a period of up to a week after their due hatching date. By this time the parents will usually have abandoned their infertile eggs so they are presumed to be void and are removed so as not to attract scavengers into the colony.

Egg Listening! © Jason McGuirk

It is inevitable that the adult terns will be disturbed during nest checks for eggs & chicks. In response to the wardens presence, the adult terns will fly around the colony in a flock, alarm calling loudly. The 'invading' warden can also expect to be dive-bombed by the parents of the nearest nest to them. In order to minimise disturbance during nest checks, visits inside the colony are constrained to 20 minutes at most during suitable weather. All the while another warden will be present along the viewing path where they can count the total number of adults in flight as well as keeping an eye out for any Hooded Crows or gulls which may take advantage of the situation.

Adult Little Tern in flight © John Fox

When the chicks are about 3 days old, the parents will often start moving their young down towards the foreshore, where they will hide amongst seaweed & debris whilst waiting for the adults to return with food. At this stage it is often difficult to keep track of the progress of each individual family so total colony chick counts are conducted first thing in the morning or late in the evening when most birds & chicks will gather on the foreshore. This will give an indication as to how well the chicks are doing.

Surveying the foreshore for chicks & fledglings © Jason McGuirk

Chicks begin to fledge at around 25 days old from early-July onwards. The age of all chicks is known as a result of nest monitoring conducted earlier in the season so the wardens are aware of the total number of fledglings present at a given time during the breeding season. This can be confirmed by again conducting colony counts along the foreshore in the morning & evening.

Protection: Wardens are present on-site 24 hours a day, 7 days a week between early-May & early-August. On arrival at the Little Tern colony, members of the public are met with a series of information signs & rope barriers on the beach & along the nearby path. The information signs provide members of the public with information about the project & the terns whilst the rope barriers designate which sections of the beach & path are off-limits to pedestrians & dogs.

Information sign & perching deterrent © Niall Keogh

A more intensive system of flexi-netting & electric fencing is constructed around the colony itself on the beach to help keep out Foxes & dogs. Plastic drinks bottles are cut open and nailed to the top of each fence post to ensure that crows do not use them as perches from which they can carry out raids on the colony. A number of CD's are also hung from the fence which is thought to help ward off crows as they appear to detest the glimmering flashes emitted by the CD's reflecting the sunlight (this has no effect on the terns).

Typical flexi-net & electric fence system © Niall Keogh

At night, a series of lamps & flashing lights are placed along the fence and a small fire is often lit on the beach to help prevent nocturnal predators such as Foxes from entering the colony. These measures do not have any negative effect on the terns. The night warden will also use a high powered lamp to scan the surrounding area for approaching Foxes or Hedgehogs. A series of humane, live capture, small mammal traps are also placed around the edge of the colony fencing to capture any Rats or Hedgehogs which may attempt to enter.

Hedgehogs - not as innocent as they look! © Niall Keogh

The presence of wardens at the colony 24 hours a day is another method of preventing predation or disturbance. Hooded Crows & Foxes are often reluctant to enter the colony if they know they are being watched or if humans are present nearby. Furthermore, under the Wildlife Act 1976, it is an offence to deliberately disturb Little Terns on their breeding grounds so the wardens are also in a position to remove pedestrians from the beach who ignore the warning signs & rope barriers and enter the colony.

Whilst the wardens can do quite a lot to prevent disturbance & predation, they are however at the mercy of the weather. High tides coupled with easterly gales pose the greatest threat to the colony and can sweep away countless nests with eggs & chicks in a single night. If this happens early enough in the season then the tern can always re-lay. There is a point in the season however that if a pair of Little Terns lose their eggs to flooding then their breeding season for that year is finished & unsuccessful. In order to try & minimise losses from flooding, any nests which are deemed by he wardens to have been laid too close to the tideline can be moved further up the beach & away from danger in the run-up to an expected high tide or storm event.

Kilcoole Little Tern colony after flooding (note how far the tideline extends up the beach) © Niall Keogh

Nest moving is a tricky process which can only be mastered through trial & error. The process begins by taking a picture & making a drawing of the nest area. Little Terns use visual markers to locate their nests on the vast, mind-boggling expanse of shingle at a breeding colony. Therefore, when conducting a nest move, the position of any prominent features in at least a 2x2m square around the nest (such as pieces of debris, large stones, brightly coloured pebbles etc) are noted. A new nest can then be created 1-2m inland from the original nest site. This is done by creating a depression in the substrate mimicking a tern nest. All the prominent features noted around the original nest are then positioned exactly around the new nest. Sometimes it is necessary to take a large quantity of the substrate from around the old nest to create an acceptable new nest (i.e. when moving a nest from an area of small pebbles into an area of sand). The eggs are then transferred carefully into the new nest.

The warden must then observe the adult tern returning to the newly positioned nest to make sure it is able to find it. In most cases, the terns are able to do so within a matter of minutes. However, if after half an hour, the adult tern has not located it's newly positioned nest, the nest must then be moved back to it's original position complete with all the prominent reference features noted at the beginning of the nest move. The tern should then be able to find it's nest again. A successful nest move can be repeated the next day, moving another 2m inland if necessary. This method, although rather intrusive has saved many nests at Kilcoole from flooding in the past.

Chicks may become prone to overexposure during periods of wet or very warm weather. In order to combat this, a number of chick shelters are placed out on the beach. These are usually made from sections of plastic piping laid out in the shingle and covered with stones & seaweed. The chicks can then shelter in them as necessary during adverse weather or even hide inside them if an aerial predator such as a Kestrel makes an attempt on the colony.

Public Liaison & the Media: Even though the section of the beach where the terns nest is blocked of to the public throughout the breeding season, we still encourage as many people as possible to come down & visit the colony to enjoy the natural spectacle. This can be done from designated viewing points on the public path alongside the colony where the wardens are more than happy to show visitors the breeding terns through their telescopes. Some nests are located quite near the path so excellent views of chicks being fed are often possible. Photographers can also be accommodated in this way, although it is worth mentioning that a licence must be obtained from the NPWS to photograph a Little Tern (or any wild bird species) on the nest.

Free information leaflets provided on site (or can be downloaded here) and a blackboard is present along the public path where the wardens update news on the progress of the colony & any interesting wildlife sightings throughout the course of the season.

The wardens will also cater for group events such as visits from BirdWatch Ireland branches, scout groups or school groups. If you are interested in organising a group event such as this then contact the wardens via e-mail. The Kilcoole Little Tern Project has been a popular source of media attention over the years and again the wardens are more than happy to take part in interviews for radio or TV.

Research: Having wardens present at a Little Tern colony throughout the course of an entire breeding season provides an excellent opportunity to conduct research into their breeding & feeding ecology as well as their migration patterns. Observational studies have shown that parent birds feed their chicks almost entirely on sandeels (Ammodytes) except for during the first couple of days after hatching, when they also feed them on gobies & small crustaceans (Amphipods) which are caught in the small estuary (The Breaches) located behind the colony.

About 2 or 3 days after hatching, chicks can be fitted with metal rings from the British Trust for Ornithology on their legs, each one with a specific code on it. If this bird is ever caught again or found dead, the details of the ring code can be submitted to a database and life history facts such as age & distance travelled since ringing can be determined.

Whilst ringing chicks, details such as weight & wing length are also taken. The nest number for each ringed chick is also noted. During subsequent visits into the colony, roaming chicks are searched for along the tideline. Those which are found have their ring number noted down as well as their weight & wing length taken again. The wardens can then see which nest it is from & how it has grown since it was last captured. By doing this, the wardens are not only obtaining data on chick growth rates, but they are also assessing the level of chick survival.