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A few things were different today from prior observations this year. (1) Along the entire colony PGs were ledge sitting. Often this was in the vicinity of openings of burrows at which we had previously seen food deliveries. There could be up to eight PGs near a burrow entrance. (2) There were no observations of eagles. Usually there are perched and flying eagles at this site. Wonder if the ledge sitting and lack of eagles are related.
For the entire duration of the survey PGs were flying to and from their ledges or doing fly-bys on the bluffs. At times there were up to 20 birds in the air. Wonder if this is related to lack of eagles also.
We generally see a PG fly in with a fish and land in the near shore and wait for an opportunity to deliver to the burrow. When ready the PG flies away from the beach to gain altitude, and perhaps to disappear from predator view, and then comes in straight to the burrow, sometimes with an escorting bird. This is the standard delivery process at this colony. However for this survey none of the observers saw a single PG in the water with fish waiting to deliver. PGs appeared to be coming straight to the burrows from wherever they caught their fish. Can this also be related to the total lack of eagles? If all the firsts today are related to lack of eagles, then the impact of eagles on PG behavior is greater than we believed.
At one of our burrows a PG repeatedly tried to gain entry to a burrow that had a PG in it. For the first observation, a a PG made three passes on the burrow. Each time there was a big scuffle with a lot of wing flapping and dust being raised, and eventually both PGs essentially fell out of the burrow, started flying, chased in the air, landed in the water, and briefly continued the scuffle. This happened two times. Case of mistaken burrow identity, courtship (!), or end of relationship?
At the North End, PGs for the second week in a row were ledge sitting and frequently taking flight for short durations and then returning to ledges. Birds on ledges were concentrated about burrows at which fish deliveries are being made, though there did not appear to be any competition for the food. What's this about ... it takes a village? On average there were about 12 ledge sitters, though I expect there were other PGs that I could not see because of the steep angle looking up at the bluff.
At burrow #15, which we call "Mustache", during one fish delivery four birds flew into the burrow at the same time. It's possible or maybe probable there is a ledge at this burrow on which two or three of the birds landed. But they all disappeared from sight into a very small area.
Most fish deliveries are made with one or sometimes two PGs flying with the delivery bird. These birds appear to be escorts and possibly diversions to confuse predators. On this Saturday, about two-thirds of the deliveries had escorts. Sometimes the escorts are birds that are clearly associated with the delivery bird; they are with the delivery bird in the water prior to both birds taking flight to the burrow, for instance. Sometimes there is no clear association between the delivery bird and the escort(s).
Lots of PG flying and ledge sitting during this survey. Difficult to distinguish between ledge sitting and visits to burrows. Sometimes PGs clearly enter burrows, but not burrows that have been identified previously as active. Do PGs seek shelter in burrows at times?
It was very foggy during this survey. Very difficult to see PGs approach burrows in time to identify whether they had fish or not. The difficulty was compounded in that there were generally a number of birds in the air (decoys?) when a delivery was made.
For the second week in a row we had a good fog in place. However, unlike last week, this week the PGs were pretty sedate. A lot of them were clustered on the beach or on rocks, and there was very little flying, in contrast to last week, when PGs were flying throughout the survey period. There were also many ledge sitters last week, and this week there were few, and those were confined to the south end of the colony, which is also where six of the seven fish deliveries were made. The north end of the colony had one fish delivery and one burrow visit. The central area of the colony had no deliveries and no visits. Overall we observed fish deliveries at three burrows this week. Two weeks ago we observed fish deliveries at nine burrows. It appears the colony is winding down, with the north and central areas ahead of the south end.
Last week we observed a chick and adult(s) in burrow #14. There was no activity at this burrow this week, and it appeared abandoned. We suspected the chick was ready to fledge and this likely happened.
There were Visits to Burrow at nine separate burrows this survey period. At six of the burrows the VBs were by two birds at the same time. Don't recall seeing so many tandem visits during past surveys this season. All of the nine burrows have been previously identified, and five of the nine have had observed fish deliveries at some time this season.
2018-08-18 @ Fort Casey North
Survey start time: 8:30, Observers: Rob and Deb Williams, Kate and Dave Krause highest PG count today (before 9:00): 17
PG count @start of survey: 17
PG count @middle of survey: 15
PG count @end of survey: 10
Starting Tide : +3.48
feet, direction: I
Total volunteer hours: 12
Looks like the season is over. No PGs were seen in close; a few were in the kelp, but most were just at the outer edge of the kelp. There were no visits to burrow and no fish deliveries; no flying around the bluffs at all. Anticipate next week will be our last survey.
It seemed that of the relatively small number of PGs identified, a high number were juveniles. We counted five at one time, and I believe there were a few more, but could not quite see markings well enough to be sure. Because of the distance of the birds from shore, many of the PG identifications were by silhouette rather than markings. So if a bird was identified by silhouette it was not characterized as adult or juvenile, just counted as a PG.