CartoDB CSS and SQL to visualize flights of gull Eric with days superimposed on each other.

ericSuperimposedDailyTorque.css

/** torque visualization */

Map {
-torque-frame-count:2048;
-torque-animation-duration:30;
-torque-time-attribute:"date_time";
-torque-aggregation-function:"count(cartodb_id)";
-torque-resolution:1;
-torque-data-aggregation:linear;
}

#bird_tracking {
    marker-fill: #C3DFE6;
    marker-fill-opacity: 0.6;
    marker-type: ellipse;
    marker-width: 4;
    marker-line-color: #FFF;
    marker-line-width: 0.5;
    marker-line-opacity: 0.3;
    comp-op: lighter;

    [frame-offset = 1] {
        marker-width: 3;
        marker-fill-opacity: 0.4;
    }
    [frame-offset = 2] {
        marker-width: 3;
        marker-fill-opacity: 0.4;
    }
    [frame-offset = 3] {
        marker-width: 2.5;
        marker-fill-opacity: 0.3;
    }
    [frame-offset = 4] {
        marker-width: 2.5;
        marker-fill-opacity: 0.3;
    }
    [frame-offset = 5] {
        marker-width: 2;
        marker-fill-opacity: 0.2;
    }
    [frame-offset = 6] {
        marker-width: 2;
        marker-fill-opacity: 0.2;
    }
}

ericSuperimposedDailyTorque.sql

WITH daily AS (
SELECT
  cartodb_id,
  the_geom,
  the_geom_webmercator,
  ('2013-06-01'::date + date_time::time)::timestamp as date_time,
	extract(month FROM date_time) as month
FROM bird_tracking
WHERE
  device_info_serial = 851
  AND userflag IS FALSE
)

SELECT * FROM daily
WHERE month = 6 OR month = 7