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Tuesday, December 8, 2015

Rusty Blackbird declines connected to Red Squirrels by Cooper's Ornithological Society

Cones, Squirrels, and Rusty Blackbird Nests: Declining Songbirds Caught in a Complex Web

The bird that’s experienced the steepest population declines in North America in recent decades is also one that few people have heard of: the Rusty Blackbird. Rusty Blackbird (Euphagus carolinus) populations have decreased by about 95% in the last fifty years, but the reasons are not well understood; it doesn’t help that their preferred breeding habitat, stunted conifers deep in the wetlands of the boreal forest, makes finding and studying them difficult. New research in The Condor: Ornithological Applications aims to disentangle some of the interacting factors that may be responsible for the decline. Shannon Buckley Luepold of the SUNY College of Environmental Science and Forestry and her colleagues spent two years collecting data on Rusty Blackbirds nests and their surrounding habitat in Maine and New Hampshire, and uncovered a web of connections between timber harvesting practices, spruce and fir cones, red squirrels, and Rusty Blackbird nesting success.

In the breeding seasons of 2011 and 2012, Buckley Luepold and her co-authors were able to locate 72 Rusty Blackbird nests and install motion-triggered, infrared cameras to watch for predators at 29 of them. Enduring swarms of biting black flies, numerous flat tires, and even a night spent stranded in the woods with a broken ATV, they also collected a variety of data on habitats where the birds nested, including vegetation density, spruce and fir cone production, and red squirrel abundance. After abundant cone production in 2011, squirrel numbers increased significantly in 2012, which is when nest survival was lower and when all of the observed red squirrel predation on eggs and nestlings occurred. A big year for cone production leads to a big year for the squirrels that eat them. This is bad news for Rusty Blackbirds, as their eggs are also on the squirrels’ menu.

“What we found was that red squirrels were indeed the most frequent predators of Rusty Blackbird nests, at least in Maine,” explains Buckley Luepold. “However, all of the red squirrel predation we observed occurred in the summer of 2012, following an abundant spruce–fir cone crop in 2011. Our results suggest that nest predation rates in Rusty Blackbirds may be driven more by ecological processes such as masting (years of higher-than-normal cone production), rather than timber harvesting, which we found not to be a strong predictor of nest survival. That said, we also found that dense vegetation was the most important predictor of nest survival, so harvest practices that reduce density of young trees, such as pre-commercial thinning, could potentially be detrimental,” says Buckley Luepold. In addition to red squirrels, cameras also caught a hawk, a Blue Jay, and even a white-tailed deer preying on Rusty Blackbird nests.

“Buckley Luepold et al.’s study elegantly chips away at the mystery surrounding what is limiting populations of Rusty Blackbirds, North America’s fastest declining songbird,” says Luke Powell of the Smithsonian Migratory Bird Center, who first suggested the possibility of a link between cone production, squirrels, and blackbird nest success. “Thanks to their work, we now know that red squirrels are the most frequent predators of Rusty Blackbird nests, and that understanding the complex relationship between red squirrels, cone cycles, and the pre-commercial thinning of softwoods near wetlands may be the key to maximizing next success.”
Nesting Rusty Blackbirds face a variety of threats. Image credit: S. Buckley Luepold
Nesting Rusty Blackbirds face a variety of threats. Image credit: S. Buckley Luepold

This camera trap image shows a red squirrel raiding a Rusty Blackbird nest and eating an egg. Image credit: S. Buckley Luepold

Saturday, November 28, 2015

Rose Tree Hawk Watch Results

American Kestrel
           I have compiled the results for the 2015 Rose Tree Park Hawk Watch and would like to share it with all the club members. This was our 17th year of counting at the hawk watch and unfortunately it was also our slowest. We totaled only 3,195 hawks this season due in large part to the lack of a large Broad-winged Hawk count. We only have one big flight day this fall and the total for the season came in at 976 birds.
           The Bald Eagle count was down slightly, but I feel that was due to the fact that since we have a nesting pair of eagles at the Springton Reservoir, this led the counters to be a little more careful in determining whether the eagle were migrating. This could have led to the count being a little on the conservative side.

Adult Bald Eagle
           Turkey Vultures were the one of two species that the yearly average increased this year.
Turkey Vulture
           Weather played an important factor all season long as most days we seem to have faced southerly winds, which proved unfavorable for migration. Below are the results for the year.

Aug 2015 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Sept 2015 206.25 0 0 112 11 0 59 211 33 0 5 967 0 9 0 0 70 10 5 0 7 6 0 1 7 1513
Oct 2015 196 396 25 34 22 0 34 472 98 0 66 9 0 84 0 1 74 19 17 0 5 2 3 2 8 1371
Nov 2015 98 84 23 0 4 0 11 58 14 0 42 0 0 66 0 0 1 2 1 0 1 4 0 0 0 311
Total 2015 500.25 480 48 146 37 0 104 741 145 0 113 976 0 159 0 1 145 31 23 0 13 12 3 3 15 3195

Golden Eagle

           As you can see from the table above we only found one Golden Eagle this year and totally missed finding any Northern Goshawks. 
           For those of you who like statistics the following table shows the biggest one day totals for all species during the past 17 years of observations.

Biggest Day Total per Species
TV 10/28/2011 436
BV 11/30/2006 36
OS 09/30/2011 47
NH 10/11/2003 14
MK 09/10/2006 1
BE 10/16/2005 20
SS 09/21/2001 217
CH 10/11/2003 37
NG 11/21/2006 3
RS 11/04/2012 63
BW 09/16/2012 3642
SW 09/25/2009 1
RT 11/07/1999 159
RL 11/11/1999 1
GE 11/03/2013 5
AK 09/15/2001 42
ML 09/21/2003 9
PG 10/05/2002 4
UV 09/04/2007 1
UA 09/04/2005 3
UB 11/04/2012 8
UE 10/10/2015 2
UF 10/17/2010 3
UR 10/11/1999 10
TOTAL 09/16/2012 3692

           The following table shows the largest year totals of each species.
Biggest Year Total per Species
TV 2011 1025
BV 2004 125
OS 2003 441
NH 2003 156
MK 2006 1
BE 2005 297
SS 2003 2033
CH 2003 354
NG 2001 20
RS 2005 278
BW 2000 13887
SW 2009 1
RT 2003 752
RL 1999 1
GE 2003 13
AK 2001 431
ML 2003 75
PG 2006 24
UV 2007 1
UA 2015 13
UB 2012 39
UE 2015 3
UF 2010 6
UR 1999 165
            I hope this little synopsis was useful and the counters including myself would like to ask for your assistance next year at the count. We can always use more volunteer counters to help take over a few days of the count. Please consider helping the dedicated volunteer counters next year. Thanks

Swallow-tailed Kite (recorded twice at Rose Tree)

Sunday, November 15, 2015

BCDC Field trip on Cape May Lewes Ferry - Nov 2015

Participants viewing the Franklin's Gull in canal before departure

          Six severely crazed birders followed my suggestion that we take a ride on the Cape May Lewes Ferry in search of seabirds. The temperature was about 45 degrees and the winds were about 40 knots making viewing conditions on the difficult side, to say the least. To give you an idea of the winds take a look at this guy hanging on for dear life.
Surfer Dude - photo by Bob Pierce
          The previous day Cape May experienced a big influx of over 100 Franklin's Gulls and today we managed to find one of the few stragglers still present today. The Franklin's Gull was located in the canal directly behind the ferry.

Franklin's Gull - our prize bird of the day - photo by Bob Pierce
Adult winter plumaged Franklin's Gull - Nick Pucinella

             Along with the Franklin's there were about 100's of Laughing Gulls, several Great Black-backed Gulls, Ring-billed and Herring Gulls, plus a Lesser Black-backed Gull.

Great Black-backed Gull by Bob Pierce

Laughing Gull - Bob Pierce

Great Black-backed Gull - 1st winter - Bob Pierce
Herring Gull - Nick Pulcinella

           We completed the accumulation of gulls with about 25 Bonaparte's Gulls about halfway across the bay. So, we ended up with seven species of gull for the day.
          Also before leaving the dock we had two Bald Eagles fly right over and spotted a Northern Harrier, Cooper's Hawk, and both species of Vultures. Once we started our adventure into the perfect storm we picked up many Northern Gannets which made a good showing today with several birds passing close by and several more following in the wake of the ferry.
Northern Gannet - Bob Pierce

Northern Gannet - Bob Pierce
          We were able to find Black and Surf Scoters in decent numbers but no luck with the White-winged Scoter.

Small Flock of Black Scoters - photo by Nick Pulcinella

Surf Scoter - Bob Pierce
Small group of Surf Scoters - Nick Pulcinella
           While in Delaware waters we picked up one lingering Royal Tern and both Red-throated and Common Loons.
Common Loon - Nick Pulcinella

Red-throated Loon - Nick Pulcinella

            Inside the jetty at Lewes we were able to add many Black Ducks, a Red-breasted Merganser, Buffleheads, and Double-crested Cormorants in the hundreds. 
Bufflehead male- Nick Pulcinella
             After we arrived back in Cape May and departed the ferry most of us headed to the hawk watch platform and were treated to several Cave Swallows swirling directly overhead with the Tree Swallows.
Cave Swallow at Hawk Watch platform - Nick Pulcinella

Cave Swallow - Nick Pulcinella

            In the bunker pond several species of waterfowl were present including Gadwall, Green-winged Teal, Northern Shovelers, Mute Swans, and American Wigeon. I said my goodbyes at this point but made a quick stop at the lighthouse pond where I found, in among all the American Wigeon, a magnificent looking Eurasian Wigeon with its rusty red head shimmering perfectly in the low sunlight of the fading day.
Eurasian Wigeon showing rusty head - Nick Pulcinella

           It was a tough day of birding but the high quality birds that were seen was well worth the effort.
Other wildlife seen today - Warthog!! - Nick Pulcinella

Cape May Lighthouse - Bob Pierce
Lewes Lighthouse - Bob Pierce

Friday, November 6, 2015

A return to Chincoteague NWR - November 2015

Endangered Delmarva Fox Squirrel
          It's been over four years since we have visited Chincoteague NWR on Assateague Island, VA. So Sharon and I made the three hour fifteen minute drive there this past week. We really lucked out on the weather as it was around 70 degrees each of the three days we were there. Upon our arrival we made a circuit around the island to see what had changed. We noticed a few new hotel chains have been supplemented to the many already existing ones, along with some restaurants, but the big change was the effect that Hurricane Sandy had on the beach area. The roads that used to be paved are now just sand which you are permitted to drive.
         The one thing that Chincoteague is famous for are the wild ponies. Usually we can spot them fairly quickly but we missed them all together the first day of our sojourn. But eventually we ran across a herd and a few singles here and there.

Dude in shorts in November viewing pony.
          Of course we also did a little birding. At the beach, I managed to add my only new state bird of the trip, a Lesser Black-backed Gull. Actually, there were quite a few. My high count was 18 gulls.
Immature LBBG

Note yellow legs and bi-color wings of LBBG

Sharon and Lesser Black-backed Gull

          While at the beach we noticed a very good flight of Northern Gannets passing fairly close to shore. There was a steady stream of them the whole time we were at the beach and the flight continued on each day we were there.

One of several thousand Northern Gannets
          There were also Sanderlings still running along the beach and three Ruddy turnstones put in an appearance. 
          I was scanning the fresh waters pools when I noticed a large flock of shorebirds flying around. They eventually flew out over the ocean and were badly backlit so I couldn't figured out what they were. Fortunately, they veered around and landed directly in front of us as we were standing on the beach. It turned out there were Willets, possibly western Willets. Any comments about the ID would be appreciated. A flock of about thirty-five.
Any comments on ID of Willets are welcomed

Gray coloration on Willets

Possible western Willets??

Photo included to show wide wing stripe

          Since the weather was so nice, we spent a lot of time on our bikes. The 3 mile inner wildlife loop of the refuge doesn't open to auto traffic until three in the afternoon so we had several hours of biking time to spend watching the birds on the wildlife loop. The surprise of the visit came when we found White Ibis in the impoundment. But not just one we found close to 80 of them, both immatures (70%) and adults.

           It's always a treat for me to encounter Tricolored Herons and we did find 13-14 of them scattered around the pools.

            Royals Terns were also present in copious numbers with lots of Forster's terns too.
Royal Terns and one Forster's on right

Forster's Tern
Pied-billed Grebe
           While back at the beach we found impressions in the sand.

             On the causeway that leads to Chincoteague Island we always stop at low tide to check out one of the coolest birds around. Feeding in the oyster beds were none other than American Oystercatchers.
American Oystercatcher

Female Boat-tailed Grackle
DC Cormorant

Sika Deer

               On one of our bike rides we came across a house that was blown off it's foundation during Hurricane Sandy.
A real fixer upper if you're interested
          So after a long Hiatus from Chincoteague we were glad to be back and promised ourselves not to wait another four years to return.
Sunset from our hotel balcony

Sunset at Tom's Cove

One Final Look

Chincoteague Light