A Fan Tale

(Photo of fantail by Jon Sullivan, CC-BY_NC, www.flickr.com/photos/mollivan_jon/26851270492/)

Jerusha Brown is in her final year of a Bachelor of Science majoring in Conservation and Ecology at Lincoln University. She spent the summer doing a research scholarship and tells us about one of her results.

Fantails are one of the most common, well-loved native birds in our towns and cities. Their beautiful fan-shaped tail and friendly “meep” makes them hard to miss when trailing through the bush or city. With their “energetic flying antics” and prolific breeding habits, fantails have managed to avoid the threatened species list that so many indigenous species are on. However, despite their abundance, fantails are particularly sensitive to major environmental disturbances.

A clear pattern in fantail numbers has just been uncovered in the long-term data set collected by Jon Sullivan , who has been monitoring biodiversity in Christchurch for over 10 years. I fortunately got the opportunity to work with some of this data through a summer scholarship programme run at Lincoln University. In doing so, we found an unmissable multiyear collapse in fantail numbers from 2011 through to 2014 (Figure 1).

Figure 1. Weekly fantail monitoring in Christchurch City, New Zealand, by Jon Sullivan. Major environmental disturbances in Christchurch over this period are marked on the graph. See the map below for the routes taken. View graph as PDF

The mention of these years carries with them an unforgettable tragedy for the people of Christchurch, as 2011 hosted the fatal February 22nd earthquake which followed the devistating September quake in 2010 . The question is, could these events have shaken fantail numbers? Looking back, it can be easy to overlook any other environmental disturbances that could have impacted on fantail numbers. While we were all getting back on our feet after the earthquakes, the snow storms in 2011 and 12 were only the icing on the damaged city. With an already warm community spirit, the snow passed easily but not for our beloved fantail.

On the 25th of July 2011 Christchurch was struck by one of the worst snow falls in 15 years, only to be repeated again unseasonably late on the 14th August 2011 and again in the following year in June. Up until the snow, fantails were spotted relatively often, even in the months following the earthquake. In August 2011 fantail numbers collapsed down to less than 12% of their pre-snow numbers, likely due to the unfortunate combination of freezing and starvation.

It is not unusual for these tiny fluff balls to dislike colder temperatures. Fantails are rarely seen in central Otago due to heavy frosts and snow fall. In the Chatham Islands, fantail populations drop in response to unusual climate conditions or “prolonged periods of cold”. Whats striking is, the earthqaukes caused more grief to the people and infrastructre of Chrstchurch then the snow storms but had little, to no detectable effect on the city’s fantails.

As for the disappearance of fantail in 2014, climate again seems the likely culprit. A quick google search reveals headlines describing 2014 as “a year of weather extremes”, with temperatures being unusually hot, dry, wet and cold throughout the year. January 2014 was recorded as the fifth driest January since 1943. On the other hand, one of the wettest and windiest day of the same year brought with it extensive flooding in parts of the city. This fluctuation in weather proved to be not ideal for sensitive fantail as numbers dropped to less than % of. Extreme weather events such as these are predicted to only get worse due to climate change.

Thankfully, unlike many other native birds, the fantail is a resilient productive bird species that is able to bounce back after disturbances. Like the residents of Christchurch after the major earthquakes, fantails have since recovered from the forces of nature and have once again flourished in the Christchurch city.

You can help continue the fantail’s resistance against majour environmental disturbances by planting native plants in your garden or by supporting the reforestation of parts of the city when opportunities arise. Planting native trees is essentially planting fantails, says Jon Sullivan. It would be fantastic to know that as we survive the tests of time, our wonderful fantail will be there flittering alongside us.

Figure 2. Jon Sullivan’s weekly run routes and all the fantails seen or heard. The red Hoon Hay-Wigram run route began in July 2008. The blue Cashmere-Hoon Hay-Somerfield route began in August 2008 with the extension up the hill added in February 2012. The green Victoria Park-Sugarloaf hill run began in November 2015. Where fantails are found is strongly correlated with where there are areas of closed canopy forest and native forest restoration plantings.

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