The house sparrow was the most abundant species in our gardens in 2009, as in 2008. The silvereye was again the second most abundant species, and starling and blackbird third and fourth most abundant. The tui was fifth, and the myna made its first appearance in the top 10, in sixth position. The greenfinch has dropped out of the top 10 (now 11th at 0.7 birds per garden). These results are national averages.
The top 10 differed slightly in different regions. For example, silvereye was the most abundant species and house sparrow second most abundant in Otago. The myna, which occurs only in the North Island, was the third most abundant species in Auckland.
Top 10 garden birds in 2009
(average number per garden)
Trends over the years
House sparrow numbers increased and silvereye numbers decreased for the second year in a row. This was unexpected. These trends were potentially influenced by changes in the regional distribution of participants from year to year (see below), because bird density differed between regions. However, they were more influenced by large changes in reported bird numbers in some regions.
|Number of birds per garden over three years, 2007–2009|
There was a large increase in house sparrow numbers in the north of the country, especially Auckland and Waikato, where the species was already most abundant. However, the increase was not so great in other parts of the country, and there was actually a decrease in house sparrow numbers in Marlborough. These changes are difficult to explain.
Silvereye numbers decreased most in the south, especially Otago and Southland, where the species was most abundant. They also decreased more in gardens where birds were fed than where they weren’t fed. Several participants commented on the decrease, and some suggested disease was the cause. They had noticed silvereyes with growths around the bill, eyes, and legs last year, and a greatly reduced number of silvereyes this year. The growths could have been avian pox, a virus that can be transmitted by contact with infected birds, when they congregate around bird feeders, for example, or by ingestion of contaminated food or water. Avian pox was detected in silvereyes in Dunedin in both 2007 and 2008 (G. Loh, DOC, pers. comm.). Little is known about this disease in New Zealand, and further investigation is warranted. Another suggestion for the low number of silvereyes was that they appeared to arrive in gardens later this year than in previous years.
Other trends were the continued increase in numbers of tui (moving from sixth to fifth most abundant species) and myna (making its first appearance in the top 10), and decrease in the number of greenfinch (now dropped out of the top 10).
These changes could be short-term variations rather than a continuing trend. Several more years’ data will be needed to confirm any long-term trends.
Of the native species, only silvereye (2nd), tui (5th) and fantail (7th) made the top 10 this year. Bellbird (16th), kereru (18th), and grey warbler (19th) occurred in the top 20. Apart from the trends in silvereye (decreasing) and tui (increasing), mentioned above, the counts of other native species were relatively stable over the three years of the survey.
Number of native birds per garden over three years, 2007–2009
|Grey Warbler||0.2||Grey Warbler||0.2||Grey Warbler||0.2|
As in previous years, birds were more common in gardens where they were fed than where they were not fed. Birds were fed in 68% of gardens in 2009 (compared with 73% in 2008 and 68% in 2007). Of the participants who fed birds, 73% put out bread, 53% seeds, 45% fat, 43% fruit, and 25% sugar-water mixture. The results confirmed previous years’ findings that a higher proportion of participants fed birds in the south than in the north of the country. In particular, a higher proportion of participants in the south fed sugar-water to birds.
Some unusual species were reported from gardens again this year. Stitchbirds were recorded in Wellington again, one in an urban garden in Karori, about 2 km from the Karori wildlife sanctuary (Zealandia) where they were introduced in 2005, and another in an urban garden in Wilton, about 4 km from Zealandia.
Kaka were also recorded in Wellington gardens, six flying over a garden in Karori about 2 km from Zealandia, and two flying over a garden in Berhampore, about 4 km from Zealandia.
Red-crowned parakeets (kakariki) were reported from an urban garden in Torbay, about 15 km from Tiritiri Matangi Island, an urban garden in Glenfield, 25 km from Tiritiri Matangi Island, and a rural garden in Otaihanga, 9 km from Kapiti Island. Three kakariki were reported to come every day to eat crab apples in a rural garden in the Wairarapa, 20 km from Tararua Forest and 60 km from Kapiti Island.
Only 18 schools participated this year. As in previous years, the house sparrow was the most abundant species in school grounds. However, the sample size is too small to make more meaningful comparisons between years.
The teacher at one school said, “This was our second year of completing the survey. We were excited to see our first native bird, the waxeye (silvereye). We hope to see tui next year when our kowhai flowers for the first time.”
Top 10 birds per school
|House sparrow||12.2||House sparrow||15.7||House sparrow||11.2|
|Rock pigeon||1.9||Fantail||1.7||Black-backed gull||1.9|
Number of participants
The number of participants was slightly lower in 2009 compared with previous years. There were 1924 valid survey forms returned in 2009 (compared with 2354 in 2008 and 2067 in 2007). A further 201 returns were invalid because the surveys were either too early, too late, or more than an hour long, or they had only ticks beside the names of birds not counts of their number.
Of the valid returns, 1808 were in home gardens, 65 in parks, 25 in school grounds, and 26 in other locations. This year, 31% of returns came from Wellington (cf. 36% last year), 15% from Auckland (cf. 4% last year), 12% from Canterbury (cf. 22% last year), and 7% from Otago (cf. 13% last year).
Participants again expressed their enthusiasm for birds. One said, “I have enjoyed doing this survey and discovered several birds that I didn't know visited my garden, e.g. bellbirds and grey warblers.” Another said, “I saw a kingfisher today sitting on the clothes line. Magic!” And a 7 year-old said, “It was lots of fun looking for birds.” One participant wrote, “Our survey team included three of our children (6, 4, and 2 years old).”
Several participants commented on the benefits of local revegetation and pest control programmes (such as those carried out by city and regional councils), noticing a considerable increase in native bird life. For example, one participant from Matangi, near Hamilton, observed tui in his garden for the first time for 20 years. Several participants from Wellington also commented that the Karori wildlife sanctuary (Zealandia) has made a significant difference to the number of native birds they see in their gardens.