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Every year, oystercatchers, plovers and terns flock to beaches across the Australian coast to lay their eggs in a shallow scratch in the sand. They usually nest in the spring and summer until the chicks are ready to fly.
However, spring and summer are also the times when most people visit the beach. And human disturbance has exacerbated breeding failures, which has contributed to local contraction and the decline of many bird populations nesting on the beach.
Take Australian fairy terns (Sternula nereis nereis) in Western Australia, the focus of my research and photography, as an example. Her 2020-21 breeding season is drawing to a close and has been relatively bad.
Fox robbery and tidal flooding wiped out several colonies. Unfathomably, a colony was also lost after a four-wheel drive completed rounds of bog in a signposted nesting site. Unleashed dogs chased brooding adults out of their nests, and photographers entered restricted access places and climbed fragile dunes to photograph nesting birds.
These man-made disturbances underscore the need for ongoing training. So let’s take a closer look at the subject and how communities and individuals can make a huge difference.
Nesting on the open beach
Birds nesting on the beach usually breed, eat, and rest in coastal habitats year round. During the breeding season, which varies between species, they build their nests above the high water mark (high tide), only 20 to 30 millimeters deep in the sand.
Some species, like the fairy tern, use clams, small stones, and organic matter like algae in and around the nest to camouflage their eggs and chicks so that predators like seagulls and ravens cannot easily spot them.
While the nests on the open beach are exposed and vulnerable, it allows the birds to spot predators early and stay close to productive foraging areas.
Still, birds nesting on the beach live a tough lifestyle. Breeding efforts are often characterized by poor reproductive success and several nesting attempts can be made each season.
Eggs and chicks remain vulnerable until the chicks can fly. This takes about 43 days for fairy terns and about 63 days for plover (Thinornis rubricollis rubricollis).
Disruptions: one of their greatest threats
Many historically important sites are now so badly disturbed that they can no longer support a successful attempt at breeding. These include the Leschenault Inlet in Bunbury, Western Australia, where fairy tern colonies regularly fail due to disruption and destruction from all-wheel drives.
Species such as the eastern plover and the fairy tern have declined so much that they are now classified as “endangered” in national environmental law. It lists human disturbance as one of the most important threatening processes.
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Birds see humans and dogs as predators. As they approach, nesting adult birds move away from the nest and chicks. For example, terns usually flee while plovers run ahead of the threat and “lead” them out of the area.
If eggs and chicks are left unattended, they are vulnerable to predation by other birds, may experience thermal stress (overheating or cooling), or become trampled because their cryptic coloring makes them difficult to spot.
In contrast to plovers and oystercatchers, fairy terns nest in groups or “colonies” that can contain up to several hundred breeding pairs. Growing in colonies has its advantages. Collective group defense behavior can include, for example, birds of prey such as herring gulls (Chroicocephalus novaehollandiae).
However, this breeding strategy can also lead to mass nesting failure. For example, in 2018 a cat that visited a colony in Mandurah, about 70 km south of Perth, at night killed six adult animals, at least 40 chicks and caused 220 adult birds to evacuate the site. In other cases, entire colonies have been lost in storm surges.
Small changes can make a big difference
Land and wildlife managers are becoming increasingly aware of fairy terns and the threats they face. Proactive and adaptive management combined with a good understanding of early breeding behavior will help improve outcomes for these endangered birds.
Point Walter in Bicton, WA is a great example of how recreational users and beach breeding birds can coexist.
Point Walter, 11 miles from the city of Perth, is a popular spot for picnicking, fishing, kite surfing, boating, and kayaking. It is also an important site for shorebirds, including three species that nest on the beach: fairy tern, red caped plover, and Australian pied flycatcher (Haematopus longirostris).
The end of the sandbar is fenced off seasonally, so the number of terns has increased steadily over the past six years. For the 2020-2021 season, the sandbank supported at least 150 couples.
The closure will also benefit the local red capped plovers and Australian pied oystercatchers who nest at the site each year.
Additionally, Mandurah City’s strong community stewardship and management interventions to protect a fairy tern colony meant this season was its most successful breeding event in more than a decade – around 110 pairs at its peak.
Interventions included temporary fences, signs, community education and increased ranger patrols. Several pairs of red caped ringed plovers also managed to raise chicks, which contributed to the success.
These examples highlight the potential for positive results across their breeding area. However, intervention during the early phase of colony formation is critical. Temporary fences, signage, and community support are some of our key tools for protecting tern colonies.
So what can you do to protect birds that are breeding on the beach?
Divide the space and watch out for signs and fences. These temporary measures help protect the birds and increase their chances of breeding
Keep dogs on a leash and away from known feeding and breeding areas
Avoid driving four-wheel drive vehicles on the beach, especially during high tide
keep cats indoors or in a litter box (enclosure)
If you see a bird nesting on the beach, report it to local authorities and keep your distance
Avoid running through flocks of birds or causing them to flee. Disturbances burn energy, which could affect breeding and migration.
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