Surveying one of the world’s rarest birds: Part two

Over the first week we were treated with some spectacular sightings, lots of calls and an exciting discovery, which filled us with optimism for the species and the survey project as a whole.

In saying that, owls are notoriously elusive so we quickly became acquainted with the challenges of owl surveying.

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One of our roles as surveyors is to record observations of owl calls. When a team member hears an owl call, they note down the estimated location and by triangulating the owl calls, we can make a few assumptions. This information will assist us to determine the number of birds on the island, where their nests might be, gather clues about the identity of the owl and its territory, and to make a start on determining their ‘relationship status.’

And trust me, it’s complicated.

The power of flight gives owls a considerable advantage to humans when it comes to moving quickly and quietly through the dense foliage. They can also throw their voice around, and when combined with geographical challenges like gullies and mountains it can be extremely difficult for the human ear to pinpoint the location of an owl call with any level of accuracy. But in spite of these challenges, the results have surpassed the team’s expectations on several occasions.

boobookweb

Our team is lucky enough to be able to utilise the information gathered from a recent community survey – as part of this work, a local with a love for a particular book and TV series had the pleasure of naming three birds around his area. Over the first week, one team had regular interactions with two different owl calls in the Palm Glen area – ‘Drogon’ and ‘Rhagear’. Using their estimates and triangulating the calls, the team located Rhagear on Thursday night just metres from the intersection point, sitting at eye level and silently contemplating their presence, so this was a huge win for the team!

The next step is to send the morning team out to attempt to locate a nest in this area by looking for scat, food remains and feathers.

 

Given that owls are most active in the hours after dusk and before sunset, the majority of the surveyor’s time is dedicated to working these periods. However, daylight is a useful tool in assisting the team to do some detective work. Rhagear was noticeably silent when spotted by the team, which is a sign that the nest is close by. Birds will avoid making noise near the nest to avoid creating any unwanted attention. The day shifts also provide opportunities for the team to note down any trees that would make good nesting sites and take notes on possible hollows.

Locating nest sites also presents a significant challenge for the team. The close cousin of the Norfolk Island morepork, the New Zealand morepork, often nests in tree hollows at ground level.

Unfortunately, the introduction of cats and the Polynesian and European rat species during different eras of Norfolk’s history make ground level nesting risky business for the local owls.

As a result, it is believed that nesting sites around 10-15 metres high with considerable top cover and surrounding foliage are the preference for the Norfolk counterparts, making it difficult for our team to spot.

Perseverance is key however, and the team made several great observations of hollows in pines and oaks across the island.

Adele, Parks Australia

 

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