Little Terns, Northern NSW

Little Terns (Sternula albifrons) are listed as endangered in NSW and vulnerable in Victoria. The main threat to our smallest tern(1) (and the closely related Fairy Tern and other beach nesting birds) is poor breeding success. This beach nesting species is vulnerable to loss of suitable breeding sites and multiple disturbances from various predators, and from weather and human recreation on beaches where they like to nest.

I have been involved now for a number of years monitoring both Little and Fairy Terns breeding on the Gippsland Lakes in Victoria near where I live, so I am familiar with the trials and tribulations of small tern breeding efforts. Recently while visiting northern NSW I found a small group of Little Terns in the Brunswick Heads Nature Reserve at the Brunswick River entrance, resting with Common and Crested Terns. 

To my delight I found one juvenile bird amongst the group. This young one was raised during the 2020/21 breeding season and over the next few months, while still mainly in fledgling plumage, it will moult the strongly marked fledgling feathers, after which it will look like an adult non breeding bird.

Where might the juvenile have been raised? 

It is not possible to know, however it is likely to be somewhere on the NSW coast north of Sydney.

On my second visit, there were eight birds in this small group.  There were 16 the day before however I did not have my camera or time to approach them so I do not know if this bigger group contained more juveniles. 

Of the eight, one was a juvenile, three were adults moulting out of breeding plumage and four were in adult non breeding plumage. One of the non-breeding birds may be a sub-adult from the previous breeding season and has not  yet reached breeding maturity. 

The photos show each of the birds in their respective plumage plus some birds in full breeding condition photographed on the Gippsland Lakes in Victoria.

Please click on photos to enlarge.

Juvenile Little Tern – at Brunswick Heads.

Size comparison between a Common Tern and the juvenile Little Tern which is close to the size of an adult Little Tern.

Adult Little Terns in breeding condition – these photos were taken on the Gippsland Lakes in Victoria where Little and Fairy Tern ranges overlap and both species breed together in the same colony. The Fairy Terns start first followed a week or two later by the Little Terns.

Fish presentation by the males to the females is an important stage in mate selection and pair bonding ahead of mating. Both parents share egg incubation and feeding of chicks.

The following photos show Little Terns in full breeding condition at the fish presentation stage.

Male with fish.

The female on the left has just accepted a fish from the male on the right.

The fish is promptly swallowed while the male looks on – the head held high is a common male behaviour after fish hand over which gives the impression the male looks quite pleased with himself.

Adults moulting out of breeding plumage – at Brunswick Heads.

Adult non breeding plumage – at Brunswick Heads.

I suspect this is a young bird from the previous breeding season that has not yet reached full adult breeding condition.

The bird on the right is in non-breeding condition, however there is little or no residual yellow at the base of the bill so this may also be a sub-adult bird? 

The bird left front is just starting to moult out of breeding plumage and the bill is changing colour. The bird on the right is more advanced in moult. The two birds at the back are in non-breeding condition.

Given the odds for breeding success are stacked against Little Terns in NSW it was especially good to find a juvenile from the 2020/21 breeding season at Brunswick Heads.

NOTE (1)

While as the name implies the Little Tern is our smallest tern the difference in size between it and the Fairy Tern is very small indeed. If the size distribution curves for the Little and Fairy Terns – typical bell curves – were overlain they would match closely with slightly more smaller birds in the Little curve compared with the Fairy curve. 

In the field the Little Terns can look slimmer in build compared with the Fairies which can look bulkier or plumper however it depends on individual birds and the way they are holding their feathers – either fluffed up or drawn in.