by MigrantWatch Admin

Watching birds often starts as a relaxing pastime and sometimes progresses into contributing to the science of ornithology. But in Israel, enthusiasts who look for migratory birds go a step further – they save lives.

Israel’s airspace is stretched to the limit, on the one hand by the national air force, which is one of the world’s biggest and on the other by heavy commercial air traffic. Twice a year, this airspace is also packed with some 500 million migratory birds, which use this narrow bottleneck of land at the junction of Europe, Asia and Africa to move between their winter and summer homes. The bird densities recorded during this period are the highest anywhere in the world.

This swarm of flying objects – natural and manmade – obviously leads to a high risk of mid-air collisions, accidents and even fatalities. The picture here shows a migrating Common Crane that crashed into a military helicopter in Israel. (Photo from Wikimedia Commons.)

But a novel initiative by scientists at the Tel Aviv University and the Israeli air force has, over the years, dramatically reduced financial losses and the loss of lives resulting from bird hits. This is achieved through a network of volunteer birdwatchers who provide constant updates over the phone to a central information repository on numbers, altitude and direction of movement of migrating bird flocks. This, combined with radar sensors, satellites, and military drones gives the air force an incredibly detailed picture of bird movements, thereby giving their pilots a chance to plan their own routes accordingly.

Not surprisingly, pilots quickly learn this motto: “Take care. We share the air.”

More reading

• BBC news
• Scientific American
• Birding Israel

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Note: In India, airports try to minimise the risk of bird strikes during take-off and landing by habitat management, removal of food sources (for scavenging birds) and by scaring birds away. See this link for some summary information about bird strikes in India.

In several cultures and folklores across India, the Pied Cuckoo is believed to herald the onset of the southwest monsoon. In May 2009, MigrantWatch started a Pied Cuckoo Campaign, in which birders from all over India were asked to report first sightings of this species. Does the Pied Cuckoo arrive before the monsoon sets in in different parts of the country? Does the monsoon arrive at a consistent interval after the first Pied Cuckoo is seen? These are some of the questions the campaign set out to address.

The campaign was taken up enthusiastically by MigrantWatch participants, with over 100 Pied Cuckoo entries to the database for 2009, and additional records from previous years. (All data collected during this campaign can be accessed on the MigrantWatch website after you login to your account.)

So did the Pied Cuckoo announce the arrival of the monsoon in different parts of India in 2009? Here are two visual depictions of the arrival of the cuckoo and the monsoon.

The 2009 monsoon
The monsoon set in nine days early on the Kerala coast (on 23 May instead of the normal 1 June) and made a good start. A cyclone in the Bay of Bengal disturbed the normal pattern just after it set in. By 25 May the southwest monsoon had moved over entire Kerala and Tamil Nadu, parts of coastal Karnataka, northeastern states, and most parts of West Bengal. Despite an early beginning, the monsoon progressed slowly after the beginning of June.

About the map and graph
The map shows ‘isolines’ (connecting locations with similar monsoon arrival dates) that depict the approximate advance of the 2009 monsoon (redrawn from this map from IMD, Pune) and the first arrival dates of the Pied Cuckoo as reported by MigrantWatch participants from locations across India.

The graph shows a scatterplot of monsoon arrival dates on the X-axis (horizontal) and first sightings of the pied cuckoo on the Y-axis (vertical). Each point corresponds to a location for which a Pied Cuckoo sighting was reported. The solid black line shows where one would expect the points to fall if each first sighting of was on exactly the day that the monsoon arrived at that location. The dashed black line indicates first sightings preceding the monsoon by five days, and the dotted black line 30 days.

Monsoon arrival dates were extracted from the isolines shown on the IMD Pune map.

For both the map and the scatter plot:

• Only sightings before 15 July 2009 have been used.
• Only the earliest sighting was used for locations with multiple sightings.
• Because there is a resident population of Pied Cuckoos in southern India, we excluded all sightings south of 15°N latitude; but we made an exception for Rishi Valley, Andhra Pradesh (13.6°N), where the species is known to not be resident.<1>

What can we infer about Pied Cuckoo migration? Might the unusual monsoon this year have altered the typical pattern? Please do write down your interpretations as comments to this Blog. If you would like to look at all sightings of Pied Cuckoo in the 2009 season, you can download them here in excel, open document format, or as a comma-delimited text file. Please also read the notes accompanying these sightings.

Note
1. It is still not clear where exactly in southern India this species is resident and where migrant. The various handbooks and field guides on Indian birds differ on this. You can help to resolve this issue by entering General Sightings of Pied Cuckoo from any time of the year into the MigrantWatch database.

Edits
This post was edited on 20 October 2009 to remove an erroneous May record of a Pied Cuckoo from Rajasthan. This record has been removed from the figures as well as the accompanying data files.