Tag Archives: White-winged Tern

White-winged or Whiskered Terns?

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The first arriving White-winged Tern, Chlidonias leucropterus, was photographed by KweeChang Ling on the 26 Sept. This was followed about a week later by a Whiskered Tern, Chlidonias hybridus, photographed by See Toh Yew Wai on 4 Oct. Both at the Serangoon Reservoir. These two “marsh terns” are winter visitors to our shores. The White-winged usually can be seen earlier in the year (July) as they also passes through Singapore on their migration south. While the rarer Whiskered Tern appeared around mid September.

Since then there were many photos of these two terns gracing the facebook pages of various groups here. Most had a hard time telling the two species apart. This is understandable as they both look very much alike in size, plumage and shape when they are in their non breeding plumage. Further plumage differences due to age added to the confusion.

The above file photo taken at the Kranji Dam showed both tern species. Try and separate them before continuing. The extreme left tern looks a little bigger, has a stouter and slightly longer bill and the black patch from the crown does not extend below the eyes. All features of a non-breeding Whiskered Tern.

whiskered tern-See Toh

Non breeding Whiskered Tern photographed at Serangoon Reservoir on 4 Oct by See Toh Yew Wai.

Now take a look at the two extreme right terns. The first thing you notice are the black round ear patches (head phones) extending below the eyes. This is a distinctive field mark of the White-winged Tern. Their bills are slightly smaller and thinner as well.

Other subtle differences are: Whiskered has slightly forked tail while the White-winged has a almost square tail. Whiskered is slightly larger than the White-winged with longer legs. Non breeding Whiskered has a greyish rump while the White-winged upper tail and rump is white.

Now that you have the different features of the two terns sorted out, try to identify the second tern from the left.

Reference: A field Guide to the Waterbirds of Asia.Wild Bird Society of Japan 1993. Field Guide to the Birds of Australia Simpson and Day 1993. A field Guide to the Birds of Thailand and South-East Asia.Craig Robson 2000. The Avifauna of Singapore. Lim Kim Seng. 2009. Edited by Francis Yap.

Straits of Singapore Pelagic Survey 5th Oct 2014

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Pelagic Team from left: Wing Chong, Alfred Chia, Tan Ju Lin, Francis Yap, Con Foley, Alan OwYong, Lim Kim Keang, Lee Tiah Khee, Willie Foo and Lim Kim Seng.

Ten members of the Bird Group set out this morning to the Straits of Singapore to begin this Autumn’s Seabirds Count. The skies were a little overcast in the early part as we cruised eastwards in semi darkness after clearing immigration. The count started with a bang when 6 Swinhoe’s Storm Petrels were seen on migration just south of St John’s Island. Unfortunately these were the only ones we encountered for the day. A worrying decline. This was followed by multiple sightings of Swift (9) and Lesser Crested Terns (11). We could not identify at least 18 of these terns due to poor morning light. The appearance of these large terns just off Kusu Island was a bit of a surprise as we normally see them further east.

The star bird of the day flew across at around 7.30 am. Some of us did not take much notice. Luckily Francis quick fingers got it on his sensor and was identified as a uncommon non-breeding Gull-billed Tern, a local tick for Francis. Later on the way back he shot another wide bodied tern which was later identified by Dave Bakewell as a first winter Common Tern.

Gull-billed Tern
(Non-breeding Gull-billed Tern)

Common Tern
(First-winter Common Tern)

A lull followed before we cut into flocks of Bridled Terns just north of Batam. On the way back more Bridled Terns were also seen at this part of the Straits. They were all flying east. In all we counted 81 Bridled Terns, the highest number tern species seen this morning. The one spot where we can expect some action was near the yellow buoy in the middle of the Straits. This is where many of the terns rest and where Jaegers have been seen harassing them for food. It was missing most probably taken after after the savaging the wreck below.

Bridled Tern
(Bridled Tern perching on flotsam ready to fly)

Bridled Tern
(Bridled Tern in flight)

As we approached the seas off Changi, the boat skipper was looking for floating debris as most of the visiting Aleutian Terns use them to rest. The seas were rather clean this morning but eventually we found some and with it the Aleutian Terns. The first one was a juvenile with a brown neck, a plumage we have not come across before. The total count for the Aleutian Tern was 12, including one off Kusu Island on our way back.

Aleutian Tern
(Adult Aleutian Tern in flight)

Aleutian Tern
(Juvenile Aleutian Tern)

Aleutian Tern
(Adult non-breeding Aleutian Tern)

Aleutian Tern
(A successful hunt for fish by an adult Aleutian Tern)

In between 15 Marsh Terns, mainly White-winged and a Little Terns were seen.

White-winged Tern
(Adult White-winged Tern losing its black breeding plumage on it’s underparts)

White-winged Tern
(An adult White-winged Tern in non-breeding plumage with it’s characteristic ‘headphones’)

Total count for the day was 155 seabirds from nine species. All in a good day out. Many thanks to Alfred for organising this count and everyone for their help and company.

Photos: Francis Yap and Alan OwYong.