ML624026789

Âge

Non précisé

Sexe

Non précisé

Détails de l'observation

I aimed my spotting scope at the glowing horizon and witnessed an incredible conveyor belt of shearwaters for as far as I could see in my field of view (about 160 degrees) and as far into the distance as my view extended. With the exception of a few that were making short sweeps back against the grain of the rest, all were moving SW as they undulated above and between the waves. I set my scope against a nice glowing background and began counting birds as they passed through the field of view, starting by 5s before realizing I could not keep up and switching to counting by 20s conservatively. I reached 10,000 in 17 minutes and noticed that the density of birds was beginning to decrease slightly, so I decided to take a 1-minute video to aid in the counting. Later I scrolled through the video in slow motion and counted the number of birds every 10 seconds, which ranged from 63 to 82 per 10-sec period and a precise total of 451 per minute. I then applied this rounded rate of 450/min to the last 20 minutes of my count period, for an additional 9,000 birds added to the initial 10,000. (For quality control, I calculated the rate for the initial 10K in 17 minutes, and this equates to about 588 birds per minute, which agrees with my assessment that the rate was higher in the earlier period.) They were still moving through in high numbers when I stopped my count. To ensure that this was not a large circular flight pattern (and thus possible double-counting), I tracked them as far as I could see to the SW and they just kept moving in that direction as they disappeared into the distance. My ID of Wedge-tailed is both because this is the default abundant species for this location and I saw a few closer to shore afterward and they were pale below with a long tail. Any other shearwaters that may have been in the mix would effectively be left out since I counted conservatively. I may attach the video later.

Informations techniques

Modèle

iPhone 13

Lentille

iPhone 13 back dual wide camera 5.1mm f/1.6

ISO

100

Longueur focale

5.1 mm

Flash

Flash did not fire

f-stop

f/1.6

Vitesse d'obturation

1/121 sec

Dimensions

4030 pixels x 2536 pixels

Taille originale du fichier

1.27 MB