How bird photographers improve nesting success

Birdwatching has become an important form of ecotourism all over the world, generating significant revenue for local communities at birding hotspots. Birders are often willing to pay high prices to see rare or iconic species, and will travel from afar to find specific types of birds. In the past, birdwatching required only a pair of binoculars or a spotting scope, but today many birdwatchers enjoy photographing the birds, particularly at their nests. Since this is a delicate time of a bird’s life, the disturbance has led to questions about whether the mantra “take only photographs, leave only footprints” is quite as eco friendly as it sounds. 

According to Xiaocai Tan, an ornithologist and PhD candidate at Guangxi University in China, this focus on birds’ nests has worried scientists, who are concerned that the close proximity of humans to the nesting sites might stress the birds and negatively impact their reproductive success. She and her colleagues decided to study the effect of photographers on the nesting success of birds in the Nonggang National Nature Reserve (NNNR) in southern China. This reserve has 90 percent forest coverage and is rich in birdlife, including seven species that are globally threatened. 

Since the 2008 discovery of the Nonggang babbler, Stachyris  nonggangensis, the area has become a hotspot for birdwatching tourism, and attracts an increasing number of bird photographers. These photographers wait in groups at the nest sites for several hours to get good images of birds. Nests that are photographed are visited by between 3 and 10 people during the day. Local guides have set up blinds made of dark-colored material, 5–10 m from the nests, and observers stay within these structures. Photography occurs every day and throughout the day (6:00–18:00 ​h), unless there is strong wind or rain.

During the field work for this project, the researchers monitored 277 different bird nests belonging to 42 species. They recorded nesting success at nests where photographers were able to visit (83 nests), and compared this with the success at nests where no photographers were allowed (194 nests). Previous research in the Reserve had shown that nest predators, including other birds, mammals and reptiles, killed around 60 percent, and sometimes up to 75 percent, of the nestlings in the region, including the young of the globally vulnerable Nonggang Babbler. 

The researchers also recorded the feeding frequency of parent birds at nests with and without photographers. They did this for the five species of birds in the Reserve that are most commonly photographed at their nests. 

The results, published in the journal Avian Research, showed that, contrary to expectations, the predation rate of nests that were photographed (13.3 percent), was significantly lower than the rate seen in nests that were not photographed (62.9 percent). While birds often flush and fly away when a person comes near, it seems that in this case the visiting photographers were doing more to scare away the common nest predators than the nesting birds themselves. This finding applied both to nests where eggs were being incubated, and to those where nestlings were present. 

The scientists found no significant differences between parental feeding rates at nests that were disturbed by photographers and nests that were undisturbed. 

“In other words, the presence of the photographers increased the survival rate of the bird nestlings. Interestingly, their presence had little effect – positive or negative – on the feeding rates in those nests,” said Tan.

According to Aiwu Jiang, the investigator who led the study, this finding is totally contrary to what most scientists had expected. “Like a scarecrow, the presence of photographers seems to scare the nest predators away. Other research we’ve conducted in the same area shows that the presence of traffic noise can draw away birds’ mammalian predators.”

“Although this finding suggests that photography has a positive impact on the successful breeding of birds, it doesn’t mean that we are encouraging photographers to visit nest sites – there needs to be further assessment of other aspects of nesting, and other kinds of stress responses, before the total effect of bird photography can be understood.”

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By Alison Bosman, Earth.com Staff Writer