TERN REPORT - 1998 - Ted C. D'Eon

  • TERN REPORT 1995
  • TERN REPORT 1996
  • TERN REPORT 1997
  • TERN REPORT 1999
  • TERN REPORT 2000
  • TERN REPORT 2001
  • TERN REPORT 2002
  • THE BROTHERS, Yarmouth County, Nova Scotia
    Marine Chart of Lobster Bay


    In 1998, the number of tern nests on The Brothers declined from that of the previous year. There were 452 tern nests on N. Brother and 151 on S. Brother. 53 of these on N. Brother and 6 on S. Brother were Roseate Tern nests, for a total of 59 Roseate Tern nests in 1998, up from 54 in 1997.

    As was in 1997, there were fewer than usual numbers of Arctics on N. Brother whereas the majority on S. Brother were Arctic Terns in 1998.

    One Great Black-backed Gull nest was destroyed on each of The Brothers in 1998. One cripple gull was removed from S. Brother.

    From 59 Roseate Tern nests, perhaps 4 chicks hatched. Possibly only 2 survived to fledge. One adult Roseate Tern was found dead.

    Perhaps 30 to 40 tern chicks fledged from N. Brother; the majority of these, Common Terns.

    No tern chicks survived to fledgling on S. Brother in 1998. Possibly 50 did in 1997.

    Several factors contributed to the extremely poor outcome on The Brothers in 1998. Weather was a big factor. It was cold, wet and windy during the egg incubation period. But the main and preventable factor was egg depredation by, possibly, a single Crow, and the assumption that the terns would be in the air mobbing the Crow when they should have been on their nests incubating their eggs. Many of the eggs the Crow did not get were cold and failed to hatch.

    Royden D'Eon, at his aquaculture pens near N. Brother, reported seeing a single Crow (or at least, one Crow at a time) travelling back and forth from N. Brother to the mainland during the whole time terns were on N. Brother. In August, 1998, after the terns had left the island he started seeing 4 or 5 Crows on N. Brother at one time. I personally saw a Crow being mobbed by the terns of N. Brother several times as it made its way from N. Brother to the mainland. On one occasion I saw the crow leaving N. Brother with an egg in its bill.

    The Crow, however, appears to have been mainly involved with removing tern eggs from their nests and eating them on the island at designated secure locations. Inside a rusted 45 gallon oil drum [see photo on page 5] appears to have been the primary site for this activity. Several hundred tern eggs were eaten there. There were also a half a dozen more sites where this activity took place on N. Brother. The Crow is beleived to have been feeding its own chicks on the mainland as some were seen there.

    There was the usual, and probably minor, Owl or Hawk depredation on The Brothers in 1998.

    The use of old car tires as Roseate Tern nest shelters on N. Brother had little success, again, in 1998. One Roseate Tern laid one egg in one tire shelter. It never hatched.

    Pinch Gut I. was again with a stable, mostly Common Tern, colony in 1998. Nest numbers had increased slightly to 186.

    There were 14 tern nests on île Chespêque, Pubnico Harbour; all believed to be the Common Tern variety. By July 2, 1998, one tern chick had hatched. None are believed to have survived to fledge.

    8 tern decoys were placed on île Ferré, Pubnico Harbour, with no success.

    There were a few Arctic Terns at Gannet Rock though no tern nests were found there. A few terns were seen near Holmes Island and Round Island in 1998, however no landing was made. If some nested there it would have been a very small number. 14 Arctic Tern nests were found on Flat Island. A few terns nested on The Thrum.

    The aquaculture site adjacent to N. Brother had again, this year, no negative impact on the success of the tern colony. Royden D'Eon, owner of the aquaculture pens kept me informed of the tern and crow activity on N. Brother.


    Next spring something will have to be done about the Crow problem.

    The following is a chronological listing of my 1998 work with terns in general, of the Lobster Bay area, but especially with the Roseate Terns of The Brothers. The report also includes tern observations from other local residents.

    April 29, 1998 - My son, Nigel, and I fixed up a number of Roseate Tern nest shelters on the Northern Brother (N. Brother). The Brothers are two tiny islands about 1 km west of Lower West Pubnico, Nova Scotia, Canada.

    Roseate Tern nest shelters on N. Brother

    A few washed up lobster crates were added to last year's number of shelters by knocking off a board or two, turning them over at a suitable location and placing several heavy stones on top so they would not be moved by the elements. Other washed up boards and plywood were propped up and weighted down with stones to provide additional Roseate Tern nesting shelters. There are now approximately 35 man-made shelters on N. Brother.

    On the Southern Brother (S. Brother), located about 1 km to the south of N. Brother, we transformed another couple of washed up lobster crates into Roseate Tern Nest shelters. The nesting area on this island is perhaps 15 percent as large as on N. Brother.

    There were no gull nests to be remove from either island.

    April 30, 1998 - Nigel and I went to, and placed 8 wooden Tern decoys on, île Ferrée, Pubnico Harbour. The small rock which stands about 2 metres above the high water mark is partially covered with about 10 cm of humus. All edible plant life, except for some gooseberry and raspberry plants and a few wild roses, appears to have been eaten away by voles or other mouse-like creatures, as the soil is riddled with burrows. About 40 years ago there was a thriving tern colony here.

    May 2, 1998 - Lobster fisherman, Norman D'Eon reported 40 to 50 terns 3 or 4 km southwest of The Brothers.

    May 7, 1998 - Lobster fisherman, Réal d'Entremont reported 40 to 50 terns above N. Brother.

    May 9, 1998 - With Nigel and my cousin, Andrew D'Eon, I viewed from the boat, a mix of about 150 Common and Arctic terns on N. Brother. There were no terns on S. Brother, and no sign of any Roseate Terns yet. There were about 20 Arctic Terns feeding in the upwelling current between Round Island and Flat Island.

    May 13, 1998 - Lobster fisherman, Réal d'Entremont, reported there were about 200 terns at 6:00am on N. Brother. Nigel and I went there between 1:15pm and 1:45pm and there were no terns to be seen nor heard. Réal said that at about 1:30pm there were 50 or 60 terns just to the north of Rip Point swimming of floating on the water, very animated with bills and tails pointing skyward, in a very tight cluster a few meters accross. He compared them to a tightly packed group of eider ducklings. There was very little free room between the individuals. The skipper of the boat, Edouard D'Eon, had spotted them a half mile away and motored to the spot to see what it was. The boat had approached to within 100 feet (according to Réal) before they dispersed and flew away. He said the terns were not feeding and none were in the air. I have never heard of anything like this! Rip Point is a couple of km to the south of The Brothers.

    We removed 1 Great Black-backed Gull's nest from N. Brother, and fixed up a few more shelters.

    May 16, 1998 - Norman D'Eon reported the same as Réal did on May 13; a tight cluster of 50 or 60 terns just to the north of Rip Point. This must be some kind of pairing or courtship behaviour?

    May 17, 1998 - Nigel and I, along with Jordan Gunter, removed and destroyed 1 Great Black-backed Gull's nest from S. Brother. We found 5 Common Eider nests there also. There were about a dozen terns above the island when we arrived. We then motored to Rip Point and found no signs of terns. On N. Brother there were about 100 terns, most of which were Common. There were a few Arctics as well as 2 or 3 Roseate Terns in the flock. We found no Eider nests on N. Brother and no gull nests to remove.

    May 18, 1998 - Réal d'Entremont reported 400 to 500 terns at N. Brother.

    May 28, 1998 - N. Brother has been hit by corvid vandals. Nigel and I count 78 tern nests containing 1 or 2 eggs each. No nests of eggs look even remotely like that of the Roseate Tern, eventhough there Roseate Terns in the air.

    We found plenty of tern eggs which have been eaten; none of these appear to have been eaten where they were laid. In various sheltered sites we found the empty shells of tern eggs. The worse was inside an old, rusted 45 gallon drum where there were about 40 (forty). There could have been as many as 60 depredated eggs altogether. How many have been carried away from the island, who knows? Some lobster fishermen have reported seeing Crows on N. Brother.

    On S. Brother we found 5 tern nests and 4 viable Common Eider nests. There were no gull nests to remove from either island, however, we did chase away one cripple gull with a broken wing from S. Brother. We later captured it with the boat and released it at Abbott's Harbour.

    Nigel found the carcasses of 2 Harbour Seals on the southwest side of N. Brother. A local resident also reported the carcasses of 2 or 3 seals on the mainland adjacent to The Brothers.

    May 29, 1998 - Jerome D'Eon joined Nigel and me to The Thrum where we found 5 tern nests. The small number of terns in the air were mostly Arctic. We then continued to Little Gooseberry I. where we counted over 60 Double-crested Cormorant nests in the trees. No cormorant eggs were hatched yet. There were about 10 Common Eider nests and 5 eider ducklings were in the water near the island with some adults.

    On Channel I. there were many (probably less than 100) Great Blue Heron nests in the trees, along with 1 Osprey nest.

    June 7, 1998 - We counted 14 Arctic Tern nests on Flat Island. There were also approximately a dozen Arctic Terns above Round I. We viewed these from the boat. My crew on this day were Lester D'Eon and his brother, Andrew, and my son, Nigel.

    More tern egg depredation by crows on N. Brother. One crow was seen leaving N. Brother as we approached the island. Lester shooed away a reluctant Herring Gull upon landing. It managed to fly away on its own with some coaxing. There were more fresh tern eggs under the rusted 45 gallon drum. Lester asked if I had placed the empty egg shells under the drum to keep count. He was surprised to hear the Crows has done this on their own.

    June 9, 1998 - Nigel and I found only 4 tern nests on île Chespêque, Pubnico Harbour. There were a few terns around île Ferrée, Pubnico Harbour, but no signs of any terns nesting with the tern decoys there.

    June 11, 1998 - CENSUS DAY - The tern nest census was carried out by Nigel and me, with the company of Peter Verner and his cameraman, Charlie Dort, of CBC's Land and Sea. They are doing a story of my work with the tern colony.

    The CBC Land and Sea crew on N. Brother

    I was pleased with the numbers of nests we found, considering the amount of crow depredation which has taken place.

    We counted 452 tern nests on N. Brother, 35 of these were Roseate Tern's. On S. Brother we counted 151 nests of which 3 were Roseate's. 2 of the Eider nests on S. Brother appeared to have hatched; one more contained 3 incubating eggs, and one contained 3 ducklings and one unhatched egg. One dead female Eider was found in the gassy part of S. Brother. There was no visible nor obvious cause of death.

    Tern egg depredation by crows, on N. Brother, has been massive. Depredated tern eggs in and around the above mentionned rusted oil drum totalled over 100. There were more scattered about on the island. The figure of 116 empty tern egg shells was reached, but I am sure the actual number of depredated eggs is much higher. Feathers and wings of 4 or 5 dead adult terns on N. Brother could suggests possible depredation by owl or hawk. There were also bits of dark brown to black mammalian fur from a dead animal, alongside one bunch if tern feathers. I collected a few samples of it. Note: the "mammalian fur" was later determined to be Eider duckling down!

    Rusted 45 gal. drum with depredated tern eggs and Arctic Tern body


    N. Brother S. Brother totals
    June 7, 1990 302 28 330
    June 11, 1991 441 13 454
    June 11, 1992 413 0 413
    June 9, 1993 367 0 367
    June 8, 1994 380 0 380
    June 14, 1995 457 0 457
    June 16, 1996 554 12 566
    June 12, 1997 630 120 750
    June 11, 1998 452 151 603

    June 21, 1998 - Foggy Sunday. Nigel and I went to Gannet Rock to check out our Gannet decoys. A number of the decoys were unglued and some of the ones made of foam and gel coat or foam and epoxy had large chunks pecked out of them. 5 decoys, badly damaged from pecking were removed, leaving 46 on the rock. The fog cleared before we left Gannet Rock. There were many Black Guillemots and we passed by 3 of their nests on our way to the decoys. One nest contained 2 eggs; the other two, 1 egg each. We did not have time to do any more searching for Black Guillemot nests as my boat was tied to the Rock with 2 balloons for padding and I did not want to leave it like that for longer than absolutely necessary.

    I am sure there were more Black Guillemot nests. There were also, a few Arctic Terns in the air which may have been nesting.

    On the way to Gannet Rock we saw and heard a couple of terns at Holmes Island. If terns were nesting there, there could only be a few.

    On the way back to Abbott's Harbour we stopped by N. Brother. I went ashore for a few minutes to photograph the tern egg shells in and about the rusted oil drum. There were even more of them. The Roseate Tern presence on this island was very high; as many in the air as I have ever seen. I did not stay to check out any nests. I did not see any Crows.

    On this trip we saw one Roseate Tern a few km east of Peases I., 4 Gannets near Gannet Rock, and 1 Gannet in the bay between Peases I. and N. Brother.

    June 23, 1998 - This time to Pinch Gut I. with Nigel, Andrew D'Eon, Norbert d'Entremont, Norbert's wife, Pam, and their son, Jean-Pierre.

    We counted 186 tern nests. These were mostly Common Tern's, and about 15% of them contained hatchlings. We also found 5 or 6 Common Eider nests with incubating eggs. A few more Eider nests had already hatched. We found no gull nests, and we could not locate the merganser nest this year thouigh we saw one merganser female almost circle the island while we were there.

    No Roseate Terns were seen nor heard at Pinch Gut I.

    July 2, 1998 - Benjie Nickerson reported 14 tern nests on île Chespêque, Pubnico Harbour. He reported only one hatched tern chick.

    July 3, 1998 - Nigel and I visited The Brothers to do the yearly Roseate Tern nest count. On S. Brother we found 3 Roseate Tern nests which had not been counted before. On N. Brother we found 18 more which had not been counted on June 11, bringing the total Roseate nests to 59! The high number of Roseate nests could be due to a second nesting attempt by some terns.

    However all was not well. On S. Brother most of the Common and Arctic Tern nests were empty or had cold eggs. I found only one Common Tern nest with 2 eggs which were still being incubated. We counted 5 dead Common and Arctic Terns on S. Brother as well as 3 dead Harbour Seals. The dead terns were all found together within a metre or 2 of each other on the western beach above the high water mark.

    On N. Brother, the situation was also grim. There may have been 30 or 40 live Common Tern chicks on this island. Most of the few remaining unhatched eggs were cold. Very few nests will produce fledgelings in 1998 on The Brothers. There were many dead tern chicks and a few dead adults, including 1 dead adult Roseate Tern. Of note was what I perceived as some mammalian fur (properly identified as Eider duckling down, by Peter MacDonald on July 15) on the island, and the heads of two Common tern chick, each about 10 days old at time of death, found together. Their bodies eaten by some predator. (Owl?)

    Depredated Common Tern chicks - missing the bodies

    Many of the depredated tern eggs inside the oil drum were now crushed to small pieces, however there was still a layer of fresh egg shells there, as well as one decomposing body of either a Common or an Arctic tern.

    Some of the possible causes of the low success are

  • 1. Egg and chick depredation by Crow or other predator(s).
  • 2. The cold wind and rain during the critical incubation period.
  • ROSEATE TERN STATISTICS as of July 3, 1998:

    June 11/98 July 3/98 ---------------------- ---------------------------------- No. Nest Location Eggs Nest Status NORTHERN BROTHER 1 edge of grass 2 not recorded 2 under crate 2 1 egg (cold) 3 under shelter 1 1 chick 2 or 3 days old 4 under shelter 1 not recorded 5 under plywood 1 empty 6 under shelter 1 empty 7 under shelter 2 1 chick 1 or 2 days old 8 under shelter (cold) 1 not recorded 9 under dory bottom (cold) 1 not recorded 10 under dory bottom (cold) 1 not recorded 11 under shelter 1 1 egg (cold) 12 under shelter 2 1 egg (cold) 13 under crate 1 1 egg (cold) 14 in the open (warm) 2 not recorded 15 in the open 1 not recorded 16 under a crate 1 1 egg (broken) 17 in a tire 1 not recorded 18 in the open 1 not recorded 19 in the open 1 not recorded 20 under a pallet 1 1 egg (cold) 21 under a crate 1 1 egg (cold) 22 under a board 1 empty 23 under a board 1 not recorded 24 under crate top 1 not recorded 25 under crate top 1 not recorded 26 under wooden plank 2 not recorded 27 under wooden plank 2 not recorded 28 under wooden plank 1 not recorded 29 under wooden plank 1 not recorded 30 under a board 1 empty 31 under plywood 2 empty 32 under plywood 1 empty 33 under a board 1 empty 34 open 2 empty 35 under a stick 1 not recorded SOUTHERN BROTHER 36 under side of crate 1 not recprded 37 in the open 1 not recorded 38 under plywood 1 not recorded SOUTHERN BROTHER (July 3/98) 39 under a crate n/a 1 egg (warm) 40 under shelter n/a 1 eggs (warm) 41 under crate n/a 1 eggs (warm) NORTHERN BROTHER (July 3/98) 42 open vegetation n/a 1 dead 2 or 3 days old Roseate chick 43 open vegetation n/a 1 egg (warm) 44 open vegetation n/a 1 egg (warm) 45 open vegetation n/a 1 egg (warm) 46 under crate n/a 1 egg (cold) 47 under shelter n/a 1 egg (cold) 48 open n/a 1 egg (warm) 49 open (edge of grass) n/a 1 egg (cold) 50 under a platform n/a 1 egg (cold) 51 under dory bottom n/a 1 egg (cold) 52 under a crate n/a 1 egg (broken and cold) 53 in the open (near #13) n/a 1 egg (cold) 54 under shelter n/a 1 dead 1 or 2 day old chick 55 under wooden plank n/a 1 egg (cold) 56 under a crate n/a 1 egg (cold) 57 in the open n/a 2 eggs (cold) 58 in the open n/a 1 egg (cold) 59 under wooden plank n/a 1 egg (cold)

    Total 59 Roseate Tern nests - A NEW RECORD

    July 3, 1998 - 4 Roseate Tern chicks (2 alive and 2 dead)


    Jun/90 Jun 23/91 Jun 18/92 Jun 20/93 Jul 12/94 ?? 20 23 30 34 Jun 22/95 Jun 28/96 Jun 25/97 Jul 3/98 33 48 54 59

    July 8, 1998 - Andrew D'Eon was looking at N. Brother through binoculars from the mainland. The terns rose from the island en masse and out flew a Crow towards the mainland where Andrew could hear the caw of young Crows.

    July 15, 1998 - Andrew Boyne, Diane Amirault, and Becky Whittam of Canadian Wildlife Service (CWS), and Peter MacDonald of Nova Scotia Department of Natural Resources (DNR) made a visit to The Brothers. Upon landing on N. Brother a single Crow was seen leaving the island for the mainland, with a tern's egg in its bill. Nigel and I showed our visitors the stockpiles of empty tern egg shells in the steel drum as well as other protected places the Crow had brought the eggs to eat.

    Becky, Diane, Andrew, and Peter on N. Brother

    I showed Peter samples of what I had thought,on July 3, to be mammalian fur. He examined it and quickly came to the conclusion that it was Eider duckling down. What predator would have brought a duckling on N. Brother to take it apart? (Owl?, Hawk?)

    Only two Roseate Tern chicks, about 2 weeks old, were found and these were in or under nesting structures. We did not check out the areas now heavily vegetated with some type of mustard plants.

    Becky Whittam along with two others has been doing research and observation at a tern colony on Country Island, Guysborough County, Nova Scotia. I believe this to be her third summer there. She has published several reports on the Roseate Terns of this island.

    Becky Whittam on N. Brother holding a Roseate Tern chick

    July 16, 1998 - The CBC's Land and Sea crew returned to N. Brother to get some footage of pre-fledged Roseate Tern chicks showing the rosey breast feathers. We found the same two chicks as the previous day in exactly the same locations. The footage was shot. They were pleased.

    Nigel with the Royalsea-23 and Zodiac

    On leaving N. Brother we went to visit Royden (Roydy) D'Eon feeding his Steelhead Trout at the aquaculture pen adjacent to N. Brother. He informed us of seeing a Crow trafficking back and forth from N. Brother to the mainland. It had been doing this since June; always a single Crow. We had previously seen an heard at least 3 juvenile Crows on the mainland adjacent to N. Brother. He also commented on the cold, wet, and windy weather of early June.

    July 21, 1998 - Nigel and I drove to Drumhead, Guysborough County, where Archie Manthorne and his son Rodney took us by boat to Country Island to visit Becky Whittam, Tara Gibson and Colleen ?, and to see what they are doing there to improve and monitor the tern colony there. As we arrived there we were informed of their first Roseate Tern chick of 1998 hatching that very day.

    I was impressed by their plywood blinds, especially the one built on stilts, which they use to study the colony. I took notes and would like to build one for N. Brother for next year.

    July 25, 1998 - Réal d'Entremont came with Nigel and me to N. Brother. There appeared to be no more new Crow depredation signs. We looked for the two young Roseate Terns seen here on July 15 and 16 but could not find them. One adult Roseate Tern was, however, flying around with a long fish in its bill. This fish could have been a Sand Lance. It would fly over the vegetation in the area where we expected to see the young Roseates. I expect it had been hiding, waiting to be fed by its parents. We did not stay on the island long enough to see the feeding.

    TERN PHOTOS by Ted C. D'Eon

    Roseate Terns at N. Brother

    Roseate Tern Nest

    Roseate Tern Newly Hatched

    Roseate Tern Young

    Roseate Terns at N. Brother (July 21, 1997)

    Roseate Terns at N. Brother (July 25,1997)

    Roseate Terns at N. Brother (July 25, 1997)

    Ted C. D'Eon

    P.O. Box 100
    West Pubnico
    Nova Scotia  B0W 3S0
    phone (home)1-902-762-2097
          (FAX) 1-902-762-2885
    E-Mail to: ted@ns.sympatico.ca © Ted C. D'Eon, 1998