Phase 0 · do the renewed Spanish radars see birds?
Generated on 2026-09-03 15:00 UTC from the public Aloft bucket. Only nights with coverage ≥ 60 % are counted.
Radars: estjv = Madrid (Torrejón de Velasco); esgld = Barcelona (Gelida); esahr = Málaga (Alhaurín); essft = Cáceres (Sierra de Fuentes); ptlis = Lisbon (control, IPMA); ptprt = Porto (control, IPMA)
Criterion: a radar 'sees birds' if in spring the night density clearly exceeds the daytime one (ratio > 2), the spring night MTR is of the order of thousands of birds/km/night, the night traffic is concentrated towards the N-NE (concentration > 0.4) at more than 8 m/s, and there is night-to-night coherence between neighbouring radars.
Summary per radar and season
| radar |
season |
nights |
mtr_median |
mtr_p90 |
mtr_max |
dens_night |
dens_day |
night_day_ratio |
alt_mean_m |
coverage |
| esahr |
autumn |
13 |
|
|
|
1.01 |
0.89 |
1.1 |
1566 |
100% |
| esahr |
spring |
84 |
1,101 |
1,951 |
2,403 |
1.93 |
1.66 |
1.2 |
1650 |
100% |
| esahr |
summer |
66 |
434 |
827 |
951 |
2.12 |
1.94 |
1.1 |
1595 |
100% |
| esahr |
winter |
75 |
12,373 |
12,373 |
12,373 |
2.00 |
2.63 |
0.8 |
1594 |
100% |
| esgld |
autumn |
11 |
|
|
|
1.36 |
2.21 |
0.6 |
960 |
100% |
| esgld |
spring |
89 |
692 |
2,922 |
5,883 |
2.74 |
2.48 |
1.1 |
1128 |
100% |
| esgld |
summer |
65 |
809 |
1,406 |
2,884 |
3.68 |
4.53 |
0.8 |
1125 |
99% |
| esgld |
winter |
81 |
|
|
|
1.58 |
1.79 |
0.9 |
1060 |
100% |
| essft |
autumn |
12 |
439 |
439 |
439 |
0.34 |
0.33 |
1.0 |
1069 |
100% |
| essft |
spring |
92 |
501 |
1,649 |
3,487 |
0.73 |
0.53 |
1.4 |
1069 |
100% |
| essft |
summer |
51 |
1,856 |
2,473 |
2,727 |
1.78 |
3.31 |
0.5 |
989 |
99% |
| essft |
winter |
80 |
|
|
|
0.58 |
0.90 |
0.6 |
1133 |
100% |
| estjv |
autumn |
13 |
4,474 |
4,474 |
4,474 |
0.99 |
5.27 |
0.2 |
912 |
100% |
| estjv |
spring |
92 |
1,941 |
4,008 |
6,037 |
2.59 |
3.59 |
0.7 |
1037 |
100% |
| estjv |
summer |
62 |
1,122 |
1,822 |
2,316 |
3.01 |
4.19 |
0.7 |
1202 |
99% |
| estjv |
winter |
80 |
|
|
|
0.92 |
6.26 |
0.1 |
1026 |
100% |
| ptlis |
autumn |
17 |
2,208 |
7,029 |
8,800 |
0.98 |
0.50 |
2.0 |
616 |
100% |
| ptlis |
spring |
89 |
987 |
2,882 |
7,523 |
0.68 |
0.35 |
2.0 |
886 |
100% |
| ptlis |
summer |
91 |
2,134 |
7,115 |
20,102 |
1.69 |
0.72 |
2.4 |
673 |
100% |
| ptlis |
winter |
83 |
761 |
2,055 |
47,658 |
0.42 |
0.34 |
1.2 |
1161 |
99% |
| ptprt |
autumn |
31 |
1,223 |
2,892 |
3,171 |
0.36 |
0.28 |
1.3 |
1681 |
100% |
| ptprt |
spring |
72 |
1,530 |
3,765 |
12,322 |
0.82 |
0.35 |
2.3 |
1602 |
100% |
| ptprt |
summer |
91 |
1,135 |
3,262 |
8,148 |
1.11 |
0.26 |
4.2 |
1500 |
100% |
| ptprt |
winter |
82 |
756 |
2,640 |
4,556 |
0.38 |
0.35 |
1.1 |
1856 |
100% |
Traffic direction and speed in spring (density-weighted)
Migration = concentrated nocturnal flow towards N-NE at 8-15 m/s. Insects = scattered, slow drift.
| radar |
period |
layers_m |
ff_mean_ms |
concentration |
N |
NE |
E |
SE |
S |
SW |
W |
NW |
| estjv |
night |
600-1600 |
8.9 |
0.55 |
24 % |
32 % |
9 % |
6 % |
4 % |
3 % |
4 % |
17 % |
| estjv |
day |
600-1600 |
5.5 |
0.24 |
16 % |
21 % |
13 % |
7 % |
7 % |
10 % |
9 % |
15 % |
| esgld |
night |
600-1600 |
8.6 |
0.72 |
13 % |
61 % |
10 % |
2 % |
1 % |
2 % |
4 % |
6 % |
| esgld |
day |
600-1600 |
4.9 |
0.36 |
16 % |
21 % |
23 % |
10 % |
3 % |
3 % |
12 % |
13 % |
| esahr |
night |
1200-2000 |
7.9 |
0.45 |
24 % |
26 % |
9 % |
6 % |
4 % |
4 % |
10 % |
16 % |
| esahr |
day |
1200-2000 |
7.1 |
0.37 |
10 % |
18 % |
15 % |
5 % |
3 % |
3 % |
16 % |
31 % |
| essft |
night |
600-1600 |
8.7 |
0.69 |
36 % |
40 % |
5 % |
4 % |
4 % |
1 % |
4 % |
7 % |
| essft |
day |
600-1600 |
8.0 |
0.43 |
35 % |
9 % |
4 % |
8 % |
7 % |
4 % |
11 % |
22 % |
| ptlis |
night |
0-4800 |
8.3 |
0.11 |
25 % |
14 % |
5 % |
15 % |
16 % |
9 % |
6 % |
11 % |
| ptlis |
day |
0-4800 |
6.6 |
0.20 |
13 % |
12 % |
7 % |
34 % |
8 % |
10 % |
5 % |
11 % |
| ptprt |
night |
1000-4800 |
9.1 |
0.59 |
37 % |
28 % |
5 % |
4 % |
5 % |
4 % |
4 % |
14 % |
| ptprt |
day |
1000-4800 |
11.2 |
0.59 |
46 % |
10 % |
3 % |
3 % |
3 % |
5 % |
11 % |
19 % |
Correlation between radars (log night MTR, spring)
| radar |
esahr |
esgld |
essft |
estjv |
ptlis |
ptprt |
| radar |
|
|
|
|
|
|
| esahr |
|
|
|
|
|
|
| esgld |
|
1.00 |
|
|
-0.12 |
|
| essft |
|
|
1.00 |
|
0.31 |
|
| estjv |
|
|
|
1.00 |
0.38 |
0.45 |
| ptlis |
|
-0.12 |
0.31 |
0.38 |
1.00 |
0.45 |
| ptprt |
|
|
|
0.45 |
0.45 |
1.00 |
