Spring 2018

Ringing summary of Spring 2018, Eilat's Bird sanctuary

 

The ringing season of spring 2018 started on the 15/2/18 and ended on the 15/5/18. We conducted the catch using a constant effort method protocol that we use since spring 2014. The method includes 4 hours of trapping from first light, the same nets open every day (208 meters long) and one "Helgoland trap".

We did not use tape luring or food to attract the birds. In addition, we conducted few special ringing sessions for Swallows (with tape luring in the afternoons) and wader trapping in the sanctuary's saltpans, for sampling only.

In total, we caught 7140 birds from 90 species with 1332 retraps, 1 recovery from another Israeli station and 5 foreign recoveries. The trapping rate was similar to our average from recent years.

 

Little Reed Warbler - IBRCE Spring 2018

Photo: Noam Weiss

 

 

Catch by month

 

Spring 2018 showed very low catch on March, average catch in April and intensive catch on May. Please note the in the graph only half of February and May are displayed.

 

 

 

Daily total catch

 

During spring 2018, we noted two main migration waves. One on the last week of April, dominated by Blackcaps, Lesser Whitethroats and Eastern Olivaceous Warblers, and another on the second week of May with mainly Eastern Olivaceous Warblers, Blackcaps, Lesser Whitethroats and Garden Warblers. The usual migration waves of the end of March and the beginning of April did not show up in force as they usually do.

 

 

 

Diversity of species

 

The most common species caught were Blackcap (1,692), Lesser Whitethroat (1,139), Eastern Olivaceous Warbler (519), Chiffchaff (417), Eurasian Reed Warbler (312), Spanish Sparrow (263), Barn Swallow (244), Garden Warbler (121), Eastern Bonelli's Warbler (91) and House Sparrow (88).

 

Barred Warbler - IBRCE Spring 2018

Photo: Noam Weiss

 

During the migration wave of the end of April, diversity was high. The diversity remained relatively high also along the first half of May until we closed the official monitoring on the 15/5. We can safely say that Passerines migration (abundance and diversity) kept on going well beyond the usual migration season we know from the past, into the second half of May (we did some sampling ringing sessions and field monitoring).

 

 
 

The Physical condition of the migratory Passerines ringed in Eilat


The location of Eilat, on the main Eurasian African flyway, just past the challenging crossing of the foodless Sahara Desert, makes the Eilat bird sanctuary a crucial and important stopover site for the migratory birds. The physical condition of the migratory Passerines, reflected in their body mass and fat score (0 to 8), are clues for their energetic ability to continue their journeys north. In recent years, we have noticed significant differences in the average body mass and fat score of many species from year to year and we noticed a trend.


In some years, most species were heavy and fat while in other years most species showed low body mass and fat scores. The next charts show that in spring 2014 the fat score of all the common species and the body mass of most species was the highest while in spring 2015 it was the lowest of the last 5 springs. Spring 2018 showed relatively high levels of fat (less than spring 2014) in most common species and average in others. For this chart, we only chose Passerine species that cross the Sahara Desert.

 

 
 

A research that made by Katia Semchenko, a high school student, under our guidance, found a significant correlation between the physical conditions of the Passerines to the total catch. In years when the bird's physical condition was good, their numbers (represented in the catch) was low, while when their physical condition was poor, they arrive in Eilat in high numbers.


This research also found a significant correlation between amounts of rain south of the Sahara Desert to their physical condition and numbers in Eilat. In years when there was more rain in Al Khartoum and Al Ubeid in The Sudan, the researched Passerines showed high fat and body mass but small numbers in Eilat. While in years with less rain, the birds arrived in higher numbers but lower fat and weight. Dr. Irith Aloni from the Ben Gurion University in the Negev, found a significant correlation between rain in The Sudan and the arrival time of Lesser Whitethroats to Eilat. Rain south of the Sahara Desert was a clue for the bird's early arrival.

 

Other interesting observations

 

We trapped higher numbers than usual of some species: